ACT
RESEARCH
REPORT
No. 29
29
April, 1969
AN EMPIRICAL OCCUPATIONAL
CLASSIFICATION DERIVED FROM
A THEORY OF PERSONALITY
AND INTENDED FOR PRACTICE
AND RESEARCH
Am erican C o l l e g e T e s t i n g Program
John L. Holland
Douglas R. W hitney
Nancy S. Cole
James M. Richards, Jr.
P. 0.
Box 1 6 8 ,
Iowa C i t y ,
I owa
52240
S u m m a ry
The o r i g i n , d e v e l o p m e n t , v e r i f i c a t i o n , and r e v i s i o n of an
o c c u p a t i o n a l c l a s s i f i c a t i o n is p r e s e n t e d .
The c l a s s i f i c a t i o n
o r g a n i z e s o c c u p a t i o n s a c c o r d i n g to t h e ir d e g r e e of p s y c h o l o g i c a l
" r e l a t e d n e s s " f o l l o w i n g H o l l a n d ' s t h e o r y of p e r s o n a l i t y .
Because
of its t h e o r e t i c a l s i m p l i c i t y and e m p i r i c a l b a s e , the c l a s s i f i c a t i o n
h a s m a n y p o t e n t ia l p r a c t i c a l a p p l i c a t i o n s f o r v o c a t i o n a l g u id a n c e ,
i n d u s t r i a l p e r s o n n e l w o r k , and r e s e a r c h in e d u c a t io n , p s y c h o l o g y ,
and s o c i o l o g y .
An E m p i r i c a l O c cu p a t i o n a l C l a s s i f i c a t i o n D e r i v e d f r o m a T h e o r y
of P e r s o n a l i t y and Intended f o r P r a c t i c e and R e s e a r c h
John L. Holland, D o u g l a s R. W h itn ey , N a n c y S. Co le
J a m e s M. R i c h a r d s , Jr.^
T h i s r e p o r t p r e s e n t s a r e v i s i o n of the o c c u p a t i o n a l c l a s s i f i c a t i o n
s c h e m e f i r s t p r o p o s e d and t e s t e d in an e a r l i e r study (Holland, 1966b).
The m a n y d e s i r a b l e f e a t u r e s of this r e v i s e d c l a s s i f i c a t i o n e n h a n c e its
p o t e n t ia l v a l u e both f or r e s e a r c h and f or v o c a t i o n a l gu id an ce and
p e r s o n n e l w ork .
The O r i g i n a l C l a s s i f i c a t i o n
In 1959, Holland p r o p o s e d an a p r i o r i o c c u p a t i o n a l c l a s s i f i c a t i o n
of s i x c a t e g o r i e s . F r o m 1959 to 1965, this c l a s s i f i c a t i o n w a s u s e d in
s e v e r a l t h e o r e t i c a l s t u d i e s , but it w a s n e i t h e r d i r e c t l y t e s t e d for its
v a l u e as a c l a s s i f i c a t i o n s y s t e m nor e x p l i c i t l y d ef in ed f o r c l e a r and
e a s y u s e . L a t e r Holland (1966b) d ef in ed the m a j o r c a t e g o r i e s of the
c l a s sif ic a tio n - - R e a l i s t i c , I n te l l e c t u a l , A r t i s t i c , S o c i a l , E n t e r p r i s i n g ,
and C o n v e n t i o n a l - - in t e r m s of the s i x V o c a t i o n a l P r e f e r e n c e Inven tor y
(VPI) s c a l e s having the s a m e n a m e s . T he a s s u m p t i o n that o c c u p a t i o n a l
t i t l e s in the V PI s c a l e s d e f in e c o m p a r a b l e c a t e g o r i e s in the c l a s s i f i c a t i o n
m a d e an e x p l i c i t r e c o n s t r u c t i o n o f the c l a s s i f i c a t i o n p o s s i b l e .
To obtain the f i r s t e m p i r i c a l v e r s i o n of the c l a s s i f i c a t i o n
(Holland, 1966a), a p r o f i l e of V PI m e a n s w a s c a l c u l a t e d for s tu d en ts
plan ning to e n t e r e a c h o c c u p a t io n . An o c c u p a t i o n ’s co d ed p r o f i l e
( h i g h e s t s c a l e m e a n f i r s t , n e x t h i g h e s t s c a l e s e c o n d , etc . ) d efi ned
an o c c u p a t i o n ' s p l a c e in the c l a s s i f i c a t i o n . F o r e x a m p l e , an o c c u p a t io n
w ith a c o d e of RIES w a s p la c e d in the m a j o r c a t e g o ry - -R eal i s t i c .
The r e m a i n d e r of the c o d e i n d ic a t e d that o c c u p a t i o n ' s p a r t i c u l a r
s u b g r o u p w ith in its m a j o r c a t e g o r y . The a p p li c a t i o n of t h is p r o c e d u r e
to the V PI data f o r 1 2 , 4 3 2 c o l l e g e f r e s h m e n in 31 in s t i t u t i o n s (Abe
et al, 1965) p r o d u c e d s e p a r a t e c l a s s i f i c a t i o n s for m e n and w o m e n .
The c l a s s i f i c a t i o n for m e n incl uded all s i x m a j o r V PI c a t e g o r i e s
(R ea l i s t i c , I n t e l l e c t u a l , A r t i s t i c , S o c i a l , E n t e r p r i s i n g , and
C on v e n ti o n a l) , e a c h w it h one or m o r e s u b g r o u p s . The V PI data
f o r w o m e n y i e l d e d only fo u r m a j o r g r o u p s (I n t e ll e c t u a l , A r t i s t i c ,
S o c i a l , C o n v e n t i o n a l) w it h a n u m b e r of s u b g r o u p s w ith in e a c h of the
major categories.
T h i s f i r s t c l a s s i f i c a t i o n w a s t e s t e d f o r it s u s e f u l n e s s in a
s e r i e s of s t u d i e s . In the f i r s t study, Holland (1966a) obtained
s e v e r a l f a v o r a b l e r e s u l t s : the c l a s s i f i c a t i o n d e v e l o p e d f r o m one
-2-
s a m p l e ( N = 1 2 , 4 3 2 c o l l e g e s t u d e n t s ) p ro d u ce d e x p e c t e d r e s u l t s whe n
ap p lie d to a n o t h e r s a m p l e (N=10, 646 c o l l e g e s t u d e n t s ) . When s t u d e n t s
w e r e gro u p ed into s i x c a t e g o r i e s a c c o r d i n g to t h e i r o c c u p a t i o n a l c h o i c e ,
t h e i r h i g h e s t m e a n s c o r e o c c u r r e d on the c o r r e s p o n d i n g VPI s c a l e ;
that is , s t u d e n t s who c h o s e o c c u p a t i o n s p r e v i o u s l y c l a s s i f i e d as
" R e a l i s t i c ' 1 had the R e a l i s t i c s c a l e of the VPI a s th e ir h i g h e s t m e a n
s c o r e . A l s o , t h e i r m e a n on that s c a l e w a s h ig h e r than the R e a l i s t i c
m e a n of any o th er o c c u p a t i o n a l group. Without e x c e p t i o n , s i m i l a r
f in d in g s held f o r the r e m a i n i n g o c c u p a t i o n a l g r o u p s of m e n and w o m e n .
In a s e c o n d study, Holland (1968b) d e m o n s t r a t e d that in d iv id u al
p r o f i l e s u s i n g one , tw>o, and t h r e e s c a l e s coul d be i n t e r p r e t e d a c c o r d i n g
to h is th e o r y of p e r s o n a l i t y t y p e s . F o r e x a m p l e , R e a l i s t i c p e a k s w e r e
a s s o c i a t e d with t e c h n i c a l c o m p e t e n c i e s and m e c h a n i c a l ab ili ty ; I n t e l ­
l e c t u a l p e a k s w e r e a s s o c i a t e d w it h s c i e n t i f i c c o m p e t e n c i e s , m a t h e m a t i c a l
a b ili ty , e t c . S tu de nt s w it h the s a m e high point s c a l e can s t i l l be
d i s t i n g u i s h e d by th e ir s e c o n d h i g h e s t V PI s c a l e . And s t u d en t s w h o s e
f i r s t two h i g h e s t s c a l e s w e r e the s a m e , can s t i l l be d i s t i n g u i s h e d
by th e ir third h i g h e s t s c a l e . F o r t h e s e t h r e e l e v e l s of p r e d i c t i v e
dif f ic u l ty , 6 4- 8 4% of the t h e o r e t i c a l p r e d i c t i o n s of p e a k s for s t u d e n t s
with d i f f e r e n t c h a r a c t e r i s t i c s w e r e c o r r e c t f o r l a r g e s a m p l e s of m en
and w o m e n .
In a third study, Holland and Wh itn ey (1968) a p p lie d the
c l a s s i f i c a t i o n to lo n g it u d in a l data and ob t a in ed u n u s u a ll y e f f i c i e n t
p r e d i c t i o n s of v o c a t i o n a l a s p i r a t i o n s o v e r an 8 to 12 m o n th i n t e r v a l .
F o r e x a m p l e , 79% of the m e n and 93% of the w o m e n i n d i c a t e s u c c e s s i v e
v o c a t i o n a l c h o i c e s that w e r e d e s c r i b e d a s r e l a t e d or la w f u l r a t h e r
than ra n d o m . In t h is l a t e r study, a c o m p a r i s o n of H o l l a n d ' s ( 196 6a )
and R o e ' s (1956) c l a s s i f i c a t i o n s y s t e m s s u g g e s t e d that the o r i g i n a l
Holland c l a s s i f i c a t i o n a p p e a r e d to be s o m e w h a t m o r e e f f i c i e n t for
p r e d i c t i o n . (At the s a m e t i m e , H o l l a n d ' s s c h e m e m a y h a v e en j o y e d
s o m e a d v a n t a g e s b e c a u s e it w a s d e v e l o p e d f r o m e a r l i e r data u s in g
the s a m e s a m p l e of c o l l e g e s t u d e n t s . )
In an u n pu b li sh ed r e a n a l y s i s of f o u r - y e a r l o n g i t u d i n a l data
f r o m a n a t io n a l s a m p l e of c o l l e g e st u d en ts (Ast in & P a n o s , 1968), w e
a p p lie d the c l a s s i f i c a t i o n s c h e m e and ob ta in ed c l o s e r r e l a t i o n s h i p s
b e t w e e n s u c c e s s i v e v o c a t i o n a l c h o i c e s than had the o r i g i n a l a u t h o r s .
In s e v e r a l ot h er u n p u b li sh ed a n a l y s e s , w e agai n found h i g h e r
r e l a t i o n s h i p s b e t w e e n s u c c e s s i v e o c c u p a t i o n a l c h o i c e s (Sharp &
K r a s n e g o r , 1966; D a v i s , 1965; and o t h e r s ) . G e n e r a l l y , t h e s e
g a in s in p r e d i c t i v e e f f i c i e n c y w e r e l a r g e b e c a u s e m o s t i n f o r m a l
c l a s s i f i c a t i o n s c r e a t e c a t e g o r i e s c o n s i s t i n g of o c c u p a t i o n s known
to be p s y c h o l o g i c a l l y d i v e r s e .
F i n a l l y , R i c h a r d s (in Ho lland, 1968a) p e r f o r m e d d ia g o n a l
f a c t o r a n a l y s e s to d e t e r m i n e w h e t h e r o r not e a c h VPI s c a l e m e a s u r e s
a d i m e n s i o n in d ep en d en t of w h a t the s c a l e s have in c o m m o n . The
r e s u l t s of s e p a r a t e a n a l y s e s f o r l a r g e s a m p l e s (3, 771 m e n and 3, 492
w o m e n ) c l e a r l y d e m o n s t r a t e that e a c h s c a l e d o e s m e a s u r e s o m e t h i n g
d i f f e r e n t f r o m the o t h e r s ; or, t h e r e a r e at l e a s t s i x kind s of p e o p le .
T h e r e m a y be m o r e , but not f e w e r .
In s h o r t , the o r i g i n a l c l a s s i f i c a t i o n p r o d u c e s e f f i c i e n t
p r e d i c t i o n s , c o n t a i n s a s e t of c o n c e p t s e a c h w it h s o m e unique
v a r i a n c e , and p r o v i d e s e x p l i c i t i n t e r p r e t a t i o n s of c l a s s m e m b e r s h i p .
The R e v i s e d C l a s s i f i c a t i o n
T h e f o l l o w i n g is the l a t e s t r e v i s i o n of H o l la n d 's (1966a)
c l a s s i f i c a t i o n . F o r t h is r e v i s i o n , V o c a t i o n a l P r e f e r e n c e In v en to ry
(VPI) data f or a l a r g e s a m p l e of t w o - y e a r c o l l e g e s t u d e n t s (12, 345
m e n and 7, 968 w o m e n ) w e r e ad ded to the data obta ined in 1966
f o r f o u r - y e a r c o l l e g e s t u d e n t s . Dat a f r o m s o m e s a m p l e s of
e m p l o y e d a d u lt s w e r e a l s o added to the c l a s s i f i c a t i o n . T h e s e
a d d it io n s m a d e the c l a s s i f i c a t i o n m o r e c o m p r e h e n s i v e and
reliable.
In t h is r e v i s i o n , o c c u p a t i o n s w e r e a s s i g n e d to c l a s s e s
e x a c t l y a s b e f o r e ; that is , cod ed m e a n V PI s c o r e s of a ll s tu d en ts
a s p i r i n g to an o c c u p a t io n i n d ic a t e d an o c c u p a t i o n ' s p l a c e in the
c l a s s ifi ca tio n .
In the f i r s t c l a s s i f i c a t i o n , the a r r a n g e m e n t of s u b g r o u p s
w it h in a m a j o r c l a s s had no s p e c i a l m e a n i n g . In the r e v i s i o n ,
h o w e v e r , the m a j o r c l a s s e s and s u b c l a s s e s w e r e a r r a n g e d
a c c o r d i n g to the f o l l o w i n g h e x a g o n a l m o d e l . (See F i g u r e 1)
The h e x a g o n a l m o d e l w a s d i s c o v e r e d s o m e w h a t a c c i d e n t a l l y
w h e n w e n o t i c e d that an i n t e r c o r r e l a t i o n a l m a t r i x for the VPI
s c a l e s u s e d in the c l a s s i f i c a t i o n could be a p p r o x i m a t e d by
the d i s t a n c e s w it h in the h e x a g o n . S u b s e q u e n t e x a m i n a t i o n of
c o r r e l a t i o n m a t r i c e s f o r nine d i f f e r e n t s a m p l e s r e v e a l e d that
the h e x a g o n a l m o d e l p r o v i d e d s a t i s f a c t o r y a p p r o x i m a t i o n s .
-
F i g u r e 1:
4-
A H e x a g o n a l M o d e l fo r I n t e r p r e t a t i n g I n t e r - and
In tra-C lass Relationships
REAL
. 46
INT
The R e v i s e d O c c u p a t i o n a l C l a s s i f i c a t i o n
In the f o l l o w i n g c l a s s i f i c a t i o n note t h e s e a b b r e v i a t i o n s . U nde r
the h e a d in g " s a m p l e " "2" i n d i c a t e s two y e a r c o l l e g e s t u d e n t s and
"4" i n d i c a t e s fo u r y e a r c o l l e g e s tu d e n t s and "E" i n d i c a t e s a s a m p l e
of e m p l o y e d a d u lt s . U n d e r l i n i n g i n d i c a t e s "tied c o d e s " or i d e n t ic a l
a v e r a g e s c o r e s on the V o c a t i o n a l P r e f e r e n c e I n ven tor y.
If two and four y e a r s a m p l e s w e r e ob ta in ed f o r an o c c u p a t io n
the y a r e p l a c e d t o g e t h e r . N o t e that the c o d e s ob ta in ed f r o m
d i f f e r e n t s a m p l e s a r e u s u a l l y s i m i l a r . T h e p l a c e m e n t of
o c c u p a t i o n s with d i f f e r e n t c o d e s (two y e a r v e r s u s four y e a r )
w a s s o m e t i m e s an a m b i g u o u s d e c i s i o n .
-6-
RE AL IS TI C CLASS (MEN)
Sample
4
2
O cc u p a t i o n
Architect
A rchitectural Draftsm an
Code
RIAE
RIAE
N
83
237
RISE
RISE
RISE
RISE
( RSIE)
RISE
151
105
12
50
39
27
2
4
4
4
2
4
F orester
F orester
Geographer
In d u s t r ia l A r t s T e a c h e r
In d u s t r ia l A r t s T e a c h e r
T r a d e s & I n d u s t r ia l T e a c h e r
2
Draftsman
RIEA
2 56
2
2
4
Aviation W orker
F armer
F armer
RIES
RIES
RIES
149
190
61
2
4
2
2
2
2
4
2
4
2
A r c h i t e c t u r a l & C iv il Eng. T e c h .
C iv il E n g i n e e r i n g
E lectrical W orker
E l e c t r o n i c Eng. T e c h n i c i a n
Engineer
I n d u s t r ia l En g. T e c h n i c i a n
I n d u s t r ia l E n g i n e e r
M e c h a n i c a l Eng. T e c h n i c i a n
M echanical Engineer
M etal/M achine Worker
RIEC
RIEC
RIEC
RIEC
RIEC
RIEC
RIEC
RIEC
RIEC
RIEC
265
185
604
1.63
246
106
37
398
1 52
102
4
2
Agronom ist
Construction W orker
REIS
REIS
166
103
2
2
A i r C on d it ion in g Eng. T e c h n i c i a n
M echanics Worker
REIC
REIC
55
248
2
Printer
R ES I
66
\
-7-
I N T E L L E C T U A L C L A S S (M E N )
Sam ple
4
4
Occupation
Anthropologi s t
P h ysical Therapist
a
4
2
Sample
N
2
12
4
9
2
Phy s ic ian
2
ISAE 3 54
P h y s ic ian
( ISAR) 101
4
4
36
Biological Scientist
ISRA
2
55
Biologist
ISRE
2
N a t u r a l S c i e n c e T e a c h e r ISRE
86
5
ISRE
2
P h ysical Scientist
4
M athem atics Teacher
ISRC 138
4
IESA
4
5
Home E co n o m ist
12
IESA
P'hy s i o l o g i s t
4
2
Pharm acist
IESR 374
Pharm acist
51
IESR
Pharm acist
(I ER S ) 48
4
2
Dentist
Dentist
4
4
4
4
E
A stronome r
C hem ist
Geologist
P hysicist
E n g i n e e r / T e c h n i c ian
IRAS
IRAS
!RASE
IRAS
IRAS
14
87
19
61
58
4
E ngineering Scientist
IRAC
44
4
2
4
2
4
4
2
4
B iochem ist
Biological Scientist
Botanist
M edical T echnologist
M edical T echnologist
Oceanographer
Physical Scientist
Zoologist
IRSA
IRSA
IRSA
IRSA
IRSA
IRSA
IRSA
IRSA
15
136
12
53
9
9
54
33
4
2
4
4
4
4
4
4
4
Code
IASR
LASR
Oc cupation
Optometrist
Veterinarian
V eterinarian
X-Ray Technician
Code
IRSE
IRSE
IRSE
IRSE
C hem ical Engineer
E lectrica l Engineer
Meta l. Eng. Te ch .
94
IREA
IREA 259
IREA
19
A e r o s p a c e Eng. T e c h . IRES
C h e m i c a l Eng. T ec h . IRES
M ilitary Officer
IRES
A e r o n a u t i c a 1 Eng,
M e t a l l u r g i c a l Eng.
M a t h e m a t i c i a n / Stat.
M a t h e m a t i c ian
IERS 120
( IS E R ) 67
aS t u d e n t s and f a c u lt y f r o m t h r e e s c h o o l s of p h a r m a c y .
N
20
120
76
39
188
80
80
IREC
IREC
77
14
IRCE
(IRSE)
80
74
ARTISTIC CLASS (MEN)
S a m p l e _________O c c u p a t i o n ___________________________Code_______
A SE R
4
Speech Teacher
N
10
4
2
4
2
A c t o r - D r a m a Coa ch
C osm etologist
English Teacher
Speech/D ram a Teacher
A SE I
A SE I
ASEI
ASEI
19
5
67
40
4
4
2
4
4
4
Art Teacher
M usic Teacher
M usician
M usician
Philosopher
W riter
AS IE
ASIE
AS IE
(ASEI)
ASIE
ASIE
29
63
86
41
10
42
E
4
2
A d v e r t i s i n g Man
J o u r n a li st
Journalist
AESI
AESI
(ASEI)
46
58
62
2
Photographer
ARTS
100
4
4
F o r e i g n La n gu ag e I n t e r p r e t e r
Literature Teacher
AISE
AISE
6
10
2
4
A r t is t
A rtist
AIRS
(AISE)
179
45
-9SOCIAL CLASS (MEN)
Oc cupation
P h y s i c a l Ed. T e a c h e r
P h y s i c a l Ed. T e a c h e r
Code
N
S ER I 274
(SRIE) 272
E
4
4
4
2
4
E
Sam ple
E
4
2
4
Couns el o r
SEIA
58
2
Coun s e l o r
(SEA I) 3 6
E d u c a t i o n a l P s y c h o l o g y SEIA
9
H i s t o r ian
57
SEIA
SEIA 123
Hi s t o r ian
SEIA 202
History T eacher
16
Jr. Col. A d m i n i s t r a t o r SEIA
4
4
2
4
2
F oreign S e r v ic e Officer
Industrial P sy c h o lo g ist
S o c i o l o g is t
Sociologist
Teache r
35
S EA I
17
SEA I
S EA I
57
15
SEAI
S E A I 739
2
Policem an
SREI
4
2
4
Librarian
Librarian
S p e c i a l Ed. T e a c h e r
SRIA
(SIAR)
SRIA
2
4
2
Dental T ech n ologist
E lem entary Teacher
Social S cientist
SIER
SIER
SIER
8
1 17
50
4
2
4
Experim ental Psychol.
SIEA
F o r e i g n L a n g u a g e Inter. SIEA
Social Worker
SIEA
23
21
19
2
M ortician
SIRE
13
2
The r a p i s t
SIRA
23
2
Nurse
SIAE
34
2
4
English Teacher
F o r e i g n Lang. T e a c h e r
SA E R
SA E R
39
17
2
Social S e r v ic e Worker
SAEI
76
Samp] e
2
4
318
6
5
8
Oc c u p a t i o n
Cle r g y m a n
C lergym an
Cle r g y m a n
Clinical P s y c h o lo g ist
Psychologist
Code
SAIE
SAIE
(SAER)
SAIE
SAIE
N
32
77
47
42
137
-10-
ENTERPRISING CLASS (MEN)
S a m p l e _______ O c c u p a t i o n ____________________________ Code___________ N
4
16
ECRI
Buyer
2
2
Cloth ing T e c h n o l o g i s t
Real E state Agent
2
4
4
2
2
4
E conom is t
E conom ist
M anager/A dm inistrator
M anager/A dm inistrator
Salesm an
Salesm an
4
M a r k e t i n g Man
EC SI
45
2
R a d io /T V Announcer
ER AS
157
4
Public R elation s & A dv e rtisin g
EA CS
40
4
2
Lawyer
Lawyer
EA SI
(ESAI)
288
244
4
2
Government Officer
Sec retary
ESCA
ESC A
19
15
2
F o o d & H o t el T e c h n o l o g i s t
ES R C
137
4
4
2
E
Educational A d m in istra to r
Political Scientist
Political Scientist
Security Salesm an
ES A I
ES A I
(SEIA)
ES A I
8
76
54
37
EC RS
ECRS
ECSR
(ECIS)
ECSR
ECSR
E C SR
(ECRS)
9
43
45
14
360
1178
309
64
-11-
CONYENTIONA L CLASS (MEN)
S a m p l e ________ O c c u p a t i o n ____________________________Code___________ N
4
Cle rk
CRES
6
4
B usiness(C om m ercial) Teacher
CSER
23
2
D at a P r o c e s s i n g W o r k e r
CERI
502
4
Finance Expert
CEIS
91
2
4
Accountant
Accountant
CESR
(CERS)
605
279
IN T E L L E C T U A L CLASS (WOMEN)
S a m p l e ________ O c c u p a t i o n _____________________ ______ Code___________ N
4
IASE
8
A rchitect
4
2
4
A g ronom ist
Veterinarian
Ve te r i n a r ian
IASR
IASR
(ISAR)
15
28
16
2
Farm er
IACSR
8
4
Physicist
LARS
7
4
2
2
4
4
2
4
2
4
B iol og is t
C h e m i c a l Eng. T e c h n i c i a n
Medical Technologist
M edical Technologist
Natural Science T eacher
Physical Scientist
Phy s i c ia n
Phy s i c ia n
Zoologis t
4
2
4
4
Biochem is t
Biological Scientist
Biological S cientist
C hem ist
4
2
a
2
4
ISAE
ISAE
ISAE
(SIAE)
ISAE
ISAE
ISAE
ISAE
ISAE
40
10
127
111
45
6
79
38
13
ISAR
ISAR
ISAR
ISAR
12
42
21
25
Ma the m a t i c i a n / S t a t i sti cian
M athem atician
ISC A
(SCIA)
54
36
Pharm acist
Pha r m a c i s t
Pha r m a c ist
ISEA
(ISCE)
(SIAE)
46
7
15
a S tu de nt s and f a c u lt y f r o m th r e e s c h o o l s qf p h a r m a c y .
-13-
ARTISTIC CLASS (WOMEN)
Sample
4
4
4
2
4
4
2
4
2
4
2
2
2
_____ O c c u p a t i o n ___________________________ Code___________
A c t r e s s / D r a m a Coach
ASEI
ASEI
F o re ig n Language Interpreter
ASEI
Foreign Service W orker
ASEI
Industrial A rts T each er
ASEI
Industrial P sy c h o lo g ist
A SE I
Journalist
(ASIE)
Journalist
ASEI
M usic Teacher
ASEI
M usician
(ASIE)
M usician
ASEIC
Printer
ASEI
R a d io /T V Announcer
ASEI
Speech/D ram a Teacher
N
18
42
36
5
8
57
54
74
50
43
5
15
38
2
D raftsman
ASRE
8
4
2
4
4
4
Art Teacher
A rtis t
A rtist
Literature T each er
W rite r
ASIE
ASIE
ASIE
ASIE
ASIE
93
217
92
22
52
4
Civ il E n g i n e e r i n g
ASIC
6
2
A rchitectural Draftsman
ASIR
14
2
Photographer
AIES
17
-14SOCIAL CLASS (WOMEN)
ample
4
4
4
2
2
4
4
4
2
2
4
2
4
2
2
4
2
4
2
4
2
2
4
2
4
4
2
E
4
4
4
2
4
2
4
2
Occupation
Psychologist
Code
SEIA
N Sample
4
6
4
4
Buyer
SE A C 55
2
Educational P s y c h o lo g is tS E A C
15
F o o d & H o t el T e c h n i c i a n SE A C 53
4
Saleswom an
2
SE A C 95
Sale swoman
2
SE A C 25
4
B usiness Teacher
4
SC E A 89
C le r k
SCEA 94
4
I n d u s tr ia l Eng. T e c h
SCEA
6
Manager
SCEA 77
2
Manager
(SEAC) 22
2
Secretary
SC A E 1024
Secretary
S C A E 267
4
4
Dental T ech n ologist
SIAE
6
4
SIAE 952
N urse (Professional)
2
N urse (Professional)
(SAIE) 301
4
N u r s e (L. P. N. )
SIAE
75
4
32
2
P h ysical Therapist
SIAE
X -R ay Technician
62
SIAE
4
2
M athem atics Teacher
4
SIAC 114
Optometrist
4
SIAC
5
2
H o u s e w ife
2
SAEC 166
H o u s e w ife
(SAEI) 122
2
Lawyer
2
SAE C 48
Lawyer
2
(SAEI) 32
P u b l i c R e l a t i o n s .& Adv. SAE C 13
4
2
Clothing T e c h n o l o g i s t
43
SAEI
2
Couns e l o r
SAEI
28
Counselor
2
SAEI
76
Elem entary Teacher
S A E I 1497
2
English T eacher
S A E I 306
English Teacher
SAEI
78
F o r e i g n L a n g u a g e T e a c h . S A E I 117
F o r e i g n La n g u a g e T e a c h . S AE I
50
Historian
SAE I
24
Historian
(SAIE) 50
Occupation
History T eacher
Home Ec. T e a c h e r
Home E conom ist
Home E c o n o m is t
P h y s . Ed. T e a c h e r
P h y s . Ed. T e a c h e r
Policew om an
Social Worker
Speech Teacher
S p e c i a l Ed. T e a c h e r
Code
SAEI
SAEI
SAEI
(SEAI)
SAEI
SAEI
SAEI
SAEI
SAEI
SAEI
N
154
153
184
72
239
1 63
12
140
22
145
C osm etologist
S AC E
30
Medical Secretary
SACI
201
A eron au tical EngineerSAIE
9
A stronom er
SAIE
6
SAIE
34
C h u rc h W o r k e r
C h u rc h W o r k e r
(SAEI) 11
C l i n i c a l P s y c h o l o g i s t SAIE
48
D entist
32
SAIE
Dental Hygienist
SAIE 209
E x p e r i m e n t a l P s y c h . SAIE
12
Librarian
SAIE
33
L i b r a r ian
(SAE I) 32
SAIE
32
Political Scientist
Political Scientist
(SAEI) 16
P sychologist
SAIE
98
S o c i a l S e r v i c e W o r k e r S A I E 190
Social S cientist
SAIE
30
Sociologist
SAIE
55
Sociologist
(SAEI) 34
Teache r
SAIE :L477
Therapist
SAIE
84
Aviation Worker
Dental A ss is ta n t
SAIC
SAIC
10
110
ENTERPRISING CLASS (WOMEN)
Sam ple
4
Occupation
Marketing Woman
Code
ECSA
N
5
2
Real E state Agent
ESAC
13
C O N V E N T I O N A L CLAS S (WOMEN)
Sam ple
2
4
2
4
O c cu p at io n
Accountant
A c countant
Da ta P r o c e s s i n g W o r k e r
Code
CSEA
CSEA
CSEA
N
174
42
251
Finance Expert
CESI
7
A m a t h e m a t i c a l v e r i f i c a t i o n of the h e x a g o n a l c o n f i g u r a t i o n w a s
obtained by u sin g f a c t o r a n a l y s i s to l o c a t e the s i x V PI s c a l e s in a
t h r e e d i m e n s i o n a l s p a c e . ^ S i n c e all s i x v a r i a b l e s had high p o s i t i v e
l o a d i n g s on the f i r s t f a c t o r , w h i c h r e p r e s e n t s an o v e r a l l c h e c k i n g
ra te on the VPI (one kind of r e s p o n s e s et ) , they la y v e r y n e a r l y in
a plane a p p r o x i m a t e l y p e r p e n d i c u l a r to the f i r s t f a c t o r . F i t t i n g a
plan e to m i n i m i z e the d e v ia t i o n of the p oi n t s f r o m it and p r o j e c t i n g
the s i x p oi n t s onto t h is " b e s t - f i t t i n g " p la n e r e s u l t e d in the c o n f i g u r a ­
t i o n s for m e n in F i g u r e 2 and for w o m e n in F i g u r e 3.
The data in the i l l u s t r a t i v e h e x a g o n is for a 10% s a m p l e of 1, 234
out of 12, 345 m a l e t w o - y e a r c o l l e g e st u d en t s in 65 c o l l e g e s . A s a m p l e
of 796 out of 7 , 9 6 8 f e m a l e s in the s a m e c o l l e g e s p r o d u c e s s i m i l a r
r e s u l t s . T h is s i m p l e g e o m e t r i c m o d e l a r r a n g e s stude nt o c c u p a t i o n a l
a s p i r a t i o n s a c c o r d i n g to t h e i r p s y c h o l o g i c a l r e l a t e d n e s s , t h e r e b y
m a k in g the c l a s s i f i c a t i o n m o r e u s e f u l f o r v o c a t i o n a l g u i d a n c e and
r e s e a r c h in c a r e e r s . The h e x a g o n a l m o d e l a r r a n g e s the m a i n
c a t e g o r i e s in the f o l l o w i n g o r d e r - - R e a l i s t i c , I n t e l l e c t u a l , A r t i s t i c ,
S o c i a l , E n t e r p r i s i n g , and C o n v e n t i o n a l ( p r o c e e d i n g a rou nd the
h e x a g o n in a c l o c k w i s e d i r e c t i o n ) - - s o that a d j a c e n t m a i n c a t e g o r i e s
a r e m o s t c l o s e l y r e l a t e d . (S ee the h e x a g o n on P a g e 4. ) In g e n e r a l ,
c l o s e r e l a t i o n s h i p s a r e r e p r e s e n t e d by s h o r t d i s t a n c e s on the
h ex a g o n .
We can apply the s a m e p r i n c i p l e of a r r a n g e m e n t to the s u b g r o u p s
w ith in a m a j o r c a t e g o r y by o b s e r v i n g tne f o l l o w i n g r u l e s . Within a
m a j o r c a t e g o r y , a r r a n g e the s u b g r o u p s s o that the s e c o n d c o d e l e t t e r s
f o ll o w in c l o c k w i s e o r d e r s t a r t i n g f r o m the m a j o r c a t e g o r y ' s f i r s t co d e.
In the s a m e m a n n e r , a r r a n g e s u b g r o u p s w h o s e f i r s t two l e t t e r s a r e
i d e n t i c a l by the third (and f in a ll y , fourth) l e t t e r . F o r e x a m p l e , in
the R e a l i s t i c c a t e g o r y , R I ( R e a l i s t i c - I n t e l l e c t u a l ) s u b g r o u p s p r e c e d e
RA (R eal i s t i c - A r t i s t i c ) s u b g r o u p s , RA E ( R e a l i s t i c - A r t i s t i c - E n t e rp r i s i n g ) p r e c e d e s RAC ( R e a l i s t i c - A r t i s t i c - C o n v e n t i o n a l ) , and RLAS
( R e a l i s t i c - I n t e l l e c t u a l - A r t i s t i c - S o c i a l ) p r e c e d e s RIAC ( R e a l i s t i c I n t e l l e c t u a l - A r t i s t i c - C o n v e n t i o n a l ) . Th e a p p l i c a t i o n of this s i m p l e
rule p l a c e s the f i r s t subgr oup in a m a i n c a t e g o r y c l o s e to the m a j o r
c a t e g o r y on the right, p l a c e s the m i d d l e s u b g r o u p s at a n e u t r a l or
d is t a n t point, and p l a c e s the l a s t su bg r ou p c l o s e s t to the m a j o r
c a t e g o r y on the left .
The p r a c t i c a l o u t c o m e s of r e a r r a n g i n g the m a i n c a t e g o r i e s and
s u b c a t e g o r i e s f o l l o w i n g the h e x a g o n a l m o d e l a r e l a r g e l y u n c l e a r
-17-
Figure 2.
Configuration of six VPI scales in a "b est-fittin g " plane
from analysis of the correlation matrix for men.
INT
•
■1.0
REAL
H.C
l .c
■ SOC
-1 c
*
CONV
Figure 3.
•
ENT
Configuration of six VPI scales in a "b est-fittin g " plane
from analysis of the correlation matrix for women.
and u n t e s t e d at t h is t i m e . A r e v i e w of th is a r r a n g e m e n t d o e s s u g g e s t
that the h e x a g o n a l m o d e l p r o v i d e s a m o r e p s y c h o l o g i c a l l y b a s e d
a r r a n g e m e n t ; that is, s u b g r o u p s of o c c u p a t i o n s that s e e m to go
t o g e t h e r - - b e c a u s e of t h e i r c o d e s and t h e r e f o r e t h e i r a s s u m e d
p s y c h o l o g i c a l s i m i l a r i t y - - a p p e a r to be p l a c e d c l o s e to e a c h ot h e r
m o r e f r e q u e n t l y than in the o r i g i n a l c l a s s i f i c a t i o n . Th e v a lu e of
the h e x a g o n a l a r r a n g e m e n t for the m a in c l a s s e s is c l e a r l y s u p p o r t e d
by an e a r l i e r l o n g it u d in a l study (Holland &: Whitney, 1968). In
that study , if s t u d e n t s c h an ge d t h e i r o c c u p a t i o n a l p r e f e r e n c e , the
m a j o r i t y of s u c h c h a n g e s w e r e a c c o m p l i s h e d by m o v e m e n t to an
a d j a c e n t m a j o r c a t e g o r y w h e r e "adjacent" is d e f i n e d by the h e x a g o n a l
m o d e l . C o n c r e t e l y , a ch a n g e f r o m a R e a l i s t i c c h o i c e to an I n t e l l e c t u a l
or C o n v e n t i o n a l c h o i c e is a cha n ge to an "a djacent" c a t e g o r y . M o r e
i n v e s t i g a t i o n w i l l d e t e r m i n e the v a l u e of the h e x a g o n a l a r r a n g e m e n t
for s u b c l a s s e s al th ou g h the a r r a n g e m e n t i m p l i e s s o m e i n t e r e s t i n g
h y p o t h e s e s about the n a t u r e of r e l a t i o n s h i p s a m o n g s i m i l a r o c c u p a t i o n s .
To s u m m a r i z e , w e now a s s u m e that the r e v i s e d c l a s s i f i c a t i o n h as
the f o l l o w i n g d e s i r a b l e c h a r a c t e r i s t i c s : (a) an e x p l i c i t t h e o r y for
i n t e r p r e t i n g c l a s s m e m b e r s h i p , for o r g a n i z i n g i n f o r m a t io n about
o c c u p a t i o n s , and for r e v i s i n g the c l a s s i f i c a t i o n , (b) m u t u a l l y
e x c l u s i v e c l a s s e s , (c) e f f i c i e n t f o r e c a s t i n g a b i l i t y for s e v e r a l
p u r p o s e s , and (d) p r o v i s i o n f o r e x p l i c i t e x t e n s i o n to u n c l a s s i f i e d
o c c u p a t i o n s by the a p p l i c a t i o n of a s i n g l e , e m p i r i c a l t ec h n iq u e.
S i n c e the VP I s c a l e s a r e m e a s u r e s of p e r s o n a l i t y as w e l l as
i n t e r e s t s , and s i n c e p e o p l e w i t h s i m i l a r i n t e r e s t s h av e s i m i l a r
p e r s o n a l i t i e s , w e a s s u m e that the o c c u p a t i o n a l c l a s s i f i c a t i o n
o r g a n i z e s s i m i l a r p e r s o n a l i t i e s in s o m e p r a c t i c a l and s c i e n t i f i c
ways.
At the s a m e t i m e , the r e v i s e d c l a s s i f i c a t i o n s t i l l has s o m e
d e f i c i e n c i e s . T h ey in cl u d e (a) a l a c k of c o m p r e h e n s i v e n e s s , d e s p i t e
c l a s s i f y i n g a l l the c o m m o n o c c u p a t i o n s a s p i r e d to by 2 - and 4 y e a r c o l l e g e s t u d e n t s and (b) u n s t a b l e d e f i n i t i o n s , b e c a u s e d i f f e r e n t
s a m p l e s of o c c u p a t i o n a l a s p i r a n t s and e m p l o y e d adu lts fo r the s a m e
o c c u p a t i o n p r o d u c e s i m i l a r but n ot a l w a y s i d e n t i c a l V PI p r o f i l e s .
C o n s e q u e n t l y , the p r e c i s e p l a c e of an o c c u p a t i o n in the c l a s s i f i c a t i o n
is s o m e t i m e s u n c l e a r , (c) Th e v a lu e of the h e x a g o n a l a r r a n g e m e n t
is only p a r t i a l l y e x p l o r e d so that it should be t e r m e d p r o m i s i n g
r a t h e r than s u b s t a n t i a t e d . F i n a l l y , (d) e m p l o y e d ad ult s a m p l e s
m a y p r o v i d e d i f f e r e n t V PI p r o f i l e s , a lth o u g h a few adult s a m p l e s
in the p r e s e n t c l a s s i f i c a t i o n 'imply that this o c c u r r e n c e is a r e m o t e
possibility.
-19Some Practical U ses
The p o t e n t i a l u s e s of the c l a s s i f i c a t i o n a r e m o s t p r o m i s i n g f o r
v o c a t i o n a l g u id a n c e , p e r s o n n e l w o r k , and r e s e a r c h . In v o c a t i o n a l
g u id a n c e , the c l a s s i f i c a t i o n c a n be u s e d to o r g a n i z e v o c a t i o n a l
i n f o r m a t i o n f i l e s and r e a d i n g s . B e c a u s e the c l a s s e s and s u b c l a s s e s
a r r a n g e m a t e r i a l s a c c o r d i n g to t h e ir " r e l a t e d n e s s " - - h o w p s y c h o l o g i c a l l y
d i s t a n t one o c c u p a t i o n is f r o m an o th er, or how far one o c c u p a t i o n a l
groi^p is f r o m a n o t h e r - - s t u d e n ts can u s e the c l a s s i f i c a t i o n fo r
o c c u p a t i o n a l e x p l o r a t i o n w it h l i t t l e he lp . F o r e x a m p l e , c o u n s e l o r s
can u s e a s t u d e n t ' s c u r r e n t o c c u p a t i o n a l c h o i c e , h i s t o r y of c h o i c e s ,
or i n t e r e s t i n v e n t o r y s c o r e s to d i r e c t a s t u d e n t to a p p r o p r i a t e
o c c u p a t i o n a l m a t e r i a l s and to e n c o u r a g e h i m to lo ok a l s o at c l o s e l y
related m aterials.
The c l a s s i f i c a t i o n s ho uld a l s o h e lp i n t e r p r e t i n t e r e s t i n v e n t o r i e s ,
s tu d en t o c c u p a t i o n a l c h o i c e s , and o t h e r s tu d en t data in t e r m s of a s i n g l e
t h e o r y . To i l l u s t r a t e , a b o y ' s c h o i c e of m e c h a n i c a l e n g i n e e r i n g w o ul d
be co d ed RIEC. And, if h i s K u d er c o d e w e r e M e c h a n i c a l - S c i e n t i f i c P e r s u a s i v e - C o m p u t a t io n a l , h is p r o f i l e w o u l d be e q u i v a l e n t to the
c l a s s i f i c a t i o n c o d e of RIEC. A s t u d e n t ' s K u d er p r o f i l e can be
t r a n s l a t e d into the Holland c a t e g o r i e s . (S ee H ol lan d, 1966b, p. 37. )
The c o u n s e l o r could a l s o a s s e s s a s t u d e n t f o r h i s r e s e m b l a n c e to
a p e r s o n w it h a p e r s o n a l i t y p a t t e r n of RIEC.
Th e c o u n s e l o r m ig h t
u s e the c l a s s i f i c a t i o n to show the student o t h e r RIEC o c c u p a t i o n s
such a s c i v i l e n g i n e e r i n g o r i n d u s t r i a l e n g i n e e r i n g .
If he is u n s u r e ab out h is in it i a l c h o i c e , the s tu d en t can be d i r e c t e d
to o c c u p a t i o n s in s u c h r e l a t e d s u b g r o u p s as a v i a t i o n (RIES), f a r m i n g ,
(RIES), o r d r a f t in g (RIEA). "Un d ec id e d" s t u d e n t s o r s t u d e n t s unable
to m a k e c h o i c e s can f i r s t e x p l o r e the e n t i r e c l a s s i f i c a t i o n and then
u s e o c c u p a t i o n a l f i l e s o r g a n i z e d by the s a m e c l a s s i f i c a t i o n to obtain
sp e c ific information.
A p e r s o n ' s c o n f l i c t i n g o c c u p a t i o n a l c h o i c e s can a l s o be c l a s s i f i e d
and e x a m i n e d f o r t h e i r s p e c i a l c h a r a c t e r and p s y c h o l o g i c a l d i s t a n c e
f r o m one a n o t h e r . U s i n g the t h e o r y , a c o u n s e l o r can e x p l i c i t l y and
t h e o r e t i c a l l y d e f in e a s t u d e n t ' s o c c u p a t i o n a l c o n f l i c t - - a p r o c e s s
w h i c h m i g h t aid both the s tu d e n t and h is c o u n s e l o r . F o r e x a m p l e ,
a boy t r y in g to d e c i d e b e t w e e n e n g i n e e r i n g (RIEC) and f a r m in g ( R I E S )
should e x p e r i e n c e l i t t l e c o n f l i c t . A d i s c u s s i o n of " C M and "S" or
"C o n ve n tio n a l" and " Soc ial " t y p e s m i g h t s i m p l i f y h is d e c i s i o n .
-20In c o n t r a s t , a boy w h o is t r y i n g to d e c i d e b e t w e e n c h e m i s t r y (IRAS)
and law (ESAI) h as a m u c h m o r e d if f ic u l t t a s k b e c a u s e his i n t e r e s t
in s u c h d i v e r s e o c c u p a t i o n s m i r r o r s d i v e r s e p e r s o n a l o p in io n s about
him self.
The c l a s s i f i c a t i o n m a y aid in d u s t r i a l p e r s o n n e l w ork ; s u b g r o u p s
of s i m i l a r o c c u p a t i o n s coul d be u s e d in r e c r u i t m e n t to c e n t e r a t te n tio n
on p o t e n t i a l l y p r o f i t a b l e r e c r u i t m e n t a r e a s . F o r i n s t a n c e , if
r e c r u i t e r s n e e d t r a i n e e s for a s p e c i f i c o c c u p a t i o n and cann ot find
enough p r o s p e c t s , the c l a s s i f i c a t i o n s p e c i f i e s r e l a t e d o c c u p a t i o n s
w h i c h m i g h t y ie ld i n t e r e s t e d c a n d i d a t e s . B e c a u s e m o s t o r g a n i z a t i o n s
find that s o m e t y p e s of p e o p l e a r e m o r e s u c c e s s f u l than o t h e r s , the
c l a s s i f i c a t i o n p r o v i d e s a s y s t e m a t i c n o m e n c l a t u r e for i n t e r p r e t i n g
t h is c o m m o n o c c u r r e n c e and u s i n g the in f o r m a t i o n a c c o r d i n g l y . F o r
e x a m p l e , e m p l o y e e s w i t h lo n g and s h o r t t e n u r e can be c o m p a r e d in
t e r m s of t h e ir V PI p r o f i l e s .
F i n a l l y , and e q u a ll y i m p o r t a n t , the c l a s s i f i c a t i o n c r e a t e s s o m e
e x c i t i n g r e s e a r c h p o s s i b i l i t i e s . The f o u r - l e t t e r c o d e s p r o v i d e
t h e o r e t i c a l d e s c r i p t i o n s f o r the t y p i c a l p e r s o n in e a c h o c c u p a t i o n .
T h e s e t h e o r e t i c a l d e s c r i p t i o n s should be h el p fu l fo r i n t e r p r e t i n g
o c c u p a t i o n a l data and o c c u p a t i o n a l d i f f e r e n c e s . F o r e x a m p l e , a
m a l e s o c i a l w o r k e r (SIEA) should d i s p l a y the c h a r a c t e r i s t i c s of
S o c i a l - L n t e l l e c t u a l - E n t e r p r i s i n g - A rti sti c t y p e s and in that o r d e r .
(See Holland, 1966b for in f o r m a t i o n about the t y p e s . ) Th e c l a s s i f i c a t i o n
a l l o w s a r e s e a r c h e r s t udy ing v o c a t i o n a l b e h a v i o r to i n v e s t i g a t e a
p e r s o n ' s tr ai n i n g, o c c u p a t i o n a l a s p i r a t i o n s , and w o r k h i s t o r y
w it h in the f r a m e w o r k of a s i n g l e c l a s s i f i c a t i o n and t h e o r y . L i t e r a l l y ,
a p e r s o n ' s l i f e can be c o n s i d e r e d a s e r i e s of cod ed c h o i c e s w h i c h
can be s tud ie d f o r th e ir p a t t e r n s , s t a b i l i t y , and m a t h e m a t i c a l
r e l a t i o n s h i p s . In ot h er r e s e a r c h , the c l a s s i f i c a t i o n can be u s e d
to o r g a n i z e and i n t e r p r e t o c c u p a t i o n a l c e n s u s i n f o r m a t i o n so that
s o m e e d u c a t i o n a l and s o c i o l o g i c a l s t u d i e s w h i c h m u s t now r e l y
on cr u d e , a m b i g u o u s c l a s s i f i c a t i o n s w i l l have a m o r e c o n s t r u c t i v e
a l t e r n a t i v e . D ep en di n g upon the v a r i e t y of o c c u p a t i o n s st u d i ed and
the s i z e of the s a m p l e , a r e s e a r c h e r can u s e the m a in s i x c a t e g o r i e s ,
the t w o - , the t h r e e - , or the f o u r - l e t t e r s u b c a t e g o r i e s . The e a r l i e r
study (Holland, 1968b) d e m o n s t r a t e d that c a t e g o r i e s b e c o m e m o r e
h o m o g e n e o u s or c l e a r l y d e f in e d a s one m o v e s f r o m s i n g l e - to tw oand t h r e e - l e t t e r c o d e s . In s h o rt , a r e s e a r c h e r can m o d if y the
c l a s s i f i c a t i o n to m e e t h i s p a r t i c u l a r n e e d s .
-21 -
F oo tnote
^ F r o m the c o r r e l a t i o n m a t r i x of the s i x s c a l e s c o r e s g i v e n in
the G P M a n u a l (Holland, 1 96 8a , p. 35, 36) p r i n c i p a l c o m p o n e n t
a n a l y s e s w e r e c o m p u t e d s e p a r a t e l y fo r m e n and w o m e n . The f i r s t
t h r e e d i m e n s i o n s or f a c t o r s a c c o u n t e d f o r 78% and 76% of the t r a c e
r e s p e c t i v e l y , and the s u c c e e d i n g s t e p s u s e d only t h e s e t h r e e
dim ensions.
A l l s i x s c a l e s had l a r g e p o s i t i v e l o a d i n g s on the f i r s t f a c t o r .
T h u s , in the t h r e e - s p a c e d ef in ed by the t h r e e f a c t o r s , the s i x p oin ts
f e l l v e r y n e a r l y in a p l a n e . B y u sin g the (6 x 3) f a c t o r load ing m a t r i x
to l o c a t e the s i x p o in t s in t h i s t h r e e - s p a c e , the s m a l l e s t c h a r a c t e r i s t i c
v e c t o r of the c o v a r i a n c e m a t r i x of the t h r e e f a c t o r s i s in the d i r e c t i o n
w h i c h m i n i m i z e s the d e v i a t i o n f r o m a plan e fitting the s i x p o i n t s . The
two l a r g e s t c h a r a c t e r i s t i c v e c t o r s c o r r e s p o n d i n g l y d e f in e t h is " b e s t
fitting" p l a n e . When the p o i n t s in t h r e e - s p a c e (the s i x V P I s c a l e s )
a r e p r o j e c t e d onto th i s p la n e , the r e s u l t i s a t w o - d i m e n s i o n a l r e p r e s e n ­
ta ti o n of the s i x p o i n t s w h i c h is g i v e n in F i g u r e 2 for m e n and F i g u r e
3 for w om en.
The e x c e l l e n t f it of the p o in ts in the t h r e e - s p a c e to the plan e i s
c l e a r f r o m the f a c t that the third c h a r a c t e r i s t i c r o o t (s h o w in g d e v i a t i o n
f r o m the p lan e) a c c o u n t e d f or on ly . 2% and 1. 1% of the t r a c e f o r m e n
and w o m e n , r e s p e c t i v e l y . Thus the p r i n c i p a l v a r i a t i o n i g n o r e d in t h e s e
a n a l y s e s is that i n v o l v e d in the fo urth, fifth, and s ix t h f a c t o r s of the
o r i g i n a l c o r r e l a t i o n m a t r i x , and e v e n t h is , a s no ted , is a m i n o r s o u r c e
of v a r i a t i o n .
2
We a r e indebted to the f o l l o w i n g p e o p le f o r t h e i r c o n s t r u c t i v e
a s s i s t a n c e : Linda R. S h e v e l , L e o n a r d L. Ba ir d, C h a r l e s F.
E lto n , E v e l y n A. B o l l i n g e r , and J a n is S. Walton.
-22-
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ACT R e s e a r c h R e po r ts
T h i s r e p o r t is the t w e n t y - ninth in a s e r i e s p u b l i s h e d by the
R e s e a r c h and D e v e l o p m e n t D i v i s i o n of the A m e r i c a n C o l l e g e T e s t i n g
P r o g r a m . Th e r e s e a r c h r e p o r t s have b e e n d e p o s i t e d w it h the A m e r ­
ic a n D o c u m e n t a t i o n I n sti tu te , ADI A u x i l i a r y P u b l i c a t i o n s P r o j e c t ,
P h o t o d u p l i c a t i o n S e r v i c e , L i b r a r y of C o n g r e s s , W a s h in g t o n , D. C.
20 5 4 0 (ADI D o c u m e n t n u m b e r s and p r i c e s a r e g i v e n b e lo w . ) P h o t o ­
c o p i e s and 35 m m . m i c r o f i l m s a r e a v a i l a b l e at c o s t f r o m ADI; o r d e r
by A DI D o c u m e n t n u m b e r . A d v a n c e p a y m e n t is r e q u i r e d . M ak e c h e c k s
o r m o n e y o r d e r s p a y a b l e to: Chief, P h o t o d u p l i c a t i o n S e r v i c e , L i b r a r y
of C o n g r e s s . P r i n t e d c o p i e s a r e a v a i l a b l e f r o m the R e s e a r c h and
D evelop m en t D ivision, A m e r ic a n College T esting P rogram .
Th e r e p o r t s a r e a l s o in d e x e d by the C U R R E N T C O N T E N T S ,
E D U C A T I O N , In st it u t e f o r S c i e n t i f i c I n f o r m a t i o n , 325 C hes tn ut
S t r e e t , P h i l a d e l p h i a , P e n n s y l v a n i a 19106.
R e p o r t s p r e c e d e d by an a s t e r i s k (*) in the l i s t be low a r e
a v a i l a b l e only f r o m ADI.
*N o .
1
*No. 2
A D e s c r i p t i o n of A m e r i c a n C o l l e g e F r e s h m e n , by C. Abe,
J. L. Hol land, S. W. Lutz, &r J. M. R i c h a r d s , Jr. ,
(ADI D o c . 8554; photo, $ 8 . 7 5 ; m i c r o f i l m , $ 3 . 0 0 )
A c a d e m i c and N o n a c a d e m i c A c c o m p l i s h m e n t : C o r r e l a t e d
o r U n c o r r e l a t e d ? by J. L. H ol lan d, & J. M. R i c h a r d s , Jr. ,
(ADI D o c . 8555; photo, $ 3 . 7 5 ; m i c r o f i l m , $ 2 . 0 0 )
*No.
3 A D e s c r i p t i o n of C o l l e g e F r e s h m e n :
I. S tu d e n t s w it h D i f f e r ­
ent V o c a t i o n a l C h o i c e s , by C. A b e , & J. L. Holland
(ADI D o c . 8556; photo, $ 7 . 5 0 ; m i c r o f i l m , $ 2 . 7 5 )
*N o.
4 A D e s c r i p t i o n of C o l l e g e F r e s h m e n : II. S t u d e n t s w i t h D i f f e r ­
ent V o c a t i o n a l C h o i c e s , by C. A be, & J. L. Holland
(ADI D o c . 8557; photo, $ 7 . 5 0 ; m i c r o f i l m , $ 2 . 7 5 )
*No.
5
*N o. 6
No.
7
A D e s c r i p t i o n of Ju n io r C o l l e g e s , by J. M. R i c h a r d s , J r . ,
L. M. Rand, & L. P . Rand
(ADI D o c 8558; photo, $3 . 75; m i c r o f i l m , $2. 00)
C o m p a r a t i v e P r e d i c t i v e V a l i d i t i e s of the A m e r i c a n C o l l e g e
T e s t s and Two O t h e r S c h o l a s t i c A pt it ud e T e s t s , by L. Munday
(ADI D o c . 8559; photo, $ 2 . 5 0 ; m i c r o f i l m , $ 1 . 7 5 )
The R e l a t i o n s h i p B e t w e e n C o l l e g e G r a d e s and A d u l t A c h i e v e ­
m e n t : A R e v i e w of the L i t e r a t u r e , by D. P. Hoyt
(ADI D o c . 8632; photo, $7. 50; m i c r o f i l m , $2. 75)
ACT R e s e a r c h R e p o r ts (cont)
-No. 8
A F a c t o r A n a l y s i s of Stu de nt " E x p l a n a t io n s " of T h e i r C h o i c e
of a C o l l e g e , by J. M. R i c h a r d s , Jr. ,
J. L. Holland
(ADI D o c . 8633; photo, $3. 75; m i c r o f i l m , $2. 00)
No. 9
R e g i o n a l D i f f e r e n c e s in Ju n io r C o l l e g e s , by J. M. R i c h a r d s ,
Jr. , L. P. Rand, & L. M. Rand
(ADI D o c . 8743; photo, $ 2 . 5 0 ; m i c r o f i l m , $ 1 . 7 5 )
No.
10 A c a d e m i c D e s c r i p t i o n and P r e d i c t i o n in J u n i o r C o l l e g e s , by
D. P. Hoyt,
L. Munday
(ADI D o c . 8856; photo, $ 3 . 7 5 ; m i c r o f i l m , $ 2 . 0 0 )
No.
11
The A s s e s s m e n t of Student A c c o m p l i s h m e n t in C o l l e g e , by J. M.
R i c h a r d s , Jr. , J. L. Ho lland, & S. W. Lutz
(ADI D o c. 8955; photo, $ 3 . 7 5 ; m i c r o f i l m , $ 2 . 0 0 )
No.
12
A c a d e m i c and N o n a c a d e m i c A c c o m p l i s h m e n t in a R e p r e s e n t a t i v e
S a m p l e taken f r o m a P o p u l a t i o n of 612, 000, by J. L. Holland,
& J. M. R i c h a r d s , Jr.
(ADI D o c. 8992; photo, $3. 75; m i c r o f i l m , $2. 00)
No.
13
The P r e d i c t i o n of Stu de nt A c c o m p l i s h m e n t in C o l l e g e , by
J. M. R i c h a r d s , Jr. , J. L. Ho lland, 8* S. W. Lutz
(ADI D o c . 9020; photo, $ 5 . 0 0 ; m i c r o f i l m , $ 2 . 2 5 )
No.
14
C h a n g e s in S e l f - R a t i n g s and L if e G o a l s A m o n g S t u d e n t s at
C o l l e g e s w it h D i f f e r e n t C h a r a c t e r i s t i c s , by R. W. S k a g e r ,
J. L. Holland, & L. A. B r a s k a m p
(ADI D o c . 9069; photo, $ 3 . 7 5 ; m i c r o f i l m , $ 2 . 0 0 )
No.
15
Can C o m p u t e r s W r i t e C o l l e g e A d m i s s i o n s T e s t s ?
R i c h a r d s , Jr.
(ADI D o c . 9174; photo, $2. 50; m i c r o f i l m , $1 . 75)
No.
16
C h a n g e s in S e l f - R a t i n g s and L if e G o a l s a s R e l a t e d to St udent
A c c o m p l i s h m e n t in C o l l e g e , by R. W. S k a g e r , & L. A. B r a s k a m p
(ADI D o c . 9214; photo, $ 2 . 5 0 ; m i c r o f i l m , $ 1 . 7 5 )
No.
17
F a m i l y I n c o m e and the C h a r a c t e r i s t i c s of C o l l e g e - Bound
S t u d e n t s , by L. L. B a ir d
(ADI D o c . 9378; photo, $3. 75; m i c r o f i l m , $2. 00)
No.
18
P r e d i c t i n g a S t u d e n t ' s V o c a t i o n a l C h o i c e , by J. L. Hol lan d
& S. W. Lutz
(ADI D o c . 9433; photo, $2. 50; m i c r o f i l m , $1. 75)
No.
19
Th e E d u c a t i o n a l G o a l s of C o l l e g e - B o u n d Youth, by L.
(ADI D o c . 9472; photo, $ 5 . 0 0 ; m i c r o f i l m , $ 2 . 2 5 )
by J. M.
L. B a ir d
ACT R e s e a r c h R eports (cont)
No. 20
Who G o e s W h e r e to Ju n io r C o l l e g e ? by J. M. R i c h a r d s ,
& L. A. B r a s k a m p
(ADI D o c . 9571; photo, $ 3 . 7 5 ; m i c r o f i l m , $ 2 . 0 0 )
No. 21
P r e d i c t i n g Student A c c o m p l i s h m e n t in C o l l e g e f r o m the A CT
A s s e s s m e n t , by J. M. R i c h a r d s , Jr. , & S. W. Lutz
(ADI D o c . 9594; photo, $6. 25; m i c r o f i l m , $2. 50)
No. 22
The U n d e c i d e d S t u d e n t : How D i f f e r e n t is He? by L. L. B a ir d
(ADI D o c . 9812; photo, $3. 75; m i c r o f i l m , $ 2. 00)
No. 23
The E f f e c t s of S e l e c t i n g C o l l e g e S t u d e n t s by V a r i o u s Kinds
of Hi gh S c h o o l A c h i e v e m e n t , by L. L. B a i r d & J. M. R i c h a r d s
Jr.
(ADI D o c . 9955; photo, $ 3 . 7 5 ; m i c r o f i l m , $ 2 . 0 0 )
No. 24
Do T h e y Do What T h e y Sa y T h ey W il l D o ? by S. W. Lutz
(ADI D o c . 9988; photo, $5. 00; m i c r o f i l m , $2. 25)
No.
C h a n g e s in the V o c a t i o n a l P l a n s of C o l l e g e S t u d e n t s : O r d e r l y
or R a n d o m ? by J. L. Holland & D. R. Wh itney
(ADI D o c . 10051; photo, $3. 75; m i c r o f i l m , $2. 00)
25
Jr.
No. 26
Th e F l o w of High S c h o o l Stude nts to S c h o o l s , C o l l e g e s , and
J o b s , by L. L. B a i r d & J, L. Holland
(ADI D o c . 10053; photo, $6. 25; m i c r o f i l m , $2. 50)
No. 27
F o r e c a s t i n g A c a d e m i c S u c c e s s in S p e c i f i c C o l l e g e s , by D.
P. Hoyt
(Naps No. 00254; photo, $ 3 . 0 0 ; m i c r o f i l m , $ 1 . 0 0 )
No. 28
A D e s c r i p t i o n of G r a d u a t e s of T w o - Y e a r C o l l e g e s ,
l
, l.
B a i r d , J. M. R i c h a r d s , Jr. & L. R. S h e v e l
( D o c u m e n t n u m b e r and p r i c e u n a v a i l a b l e at t h is t im e . )
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