Problem addressed
• HTML 4.01 strict, XHTML 1.0 strict or superior
are allowed by the Italian regulations
• Distinct dominions not easily comparable
• 43% of Italian Public institutions homepages are
declared DTD strict
• Meaningful synthesis about code validity cannot
simply exclude 57% of monitored Web contents
1
Strategy
We issued an experimental approach, thereby defining a metrics to:
• quantify expected errors on a target DTD from a different one;
• evaluate 3 properties:
– validity,
– strictness,
– markup quality.
Such a metrics can be generalized to:
• approach a more general instance about comparing documents with
different DTDs.
2
Strategy (2)
We defined the expected number of errors for a given DTD as:
n~ j  xini  xi(ni  1)
We called the couple: (x'i, x''i) Errors Springing Up Rate (ESUR).
They are computed, based on a wide sample of sites according to a
couple of weighted averages on errors about DTDs.
a sample of 1000 Web sites has been used to compute x'i and x''i as
follows:
1

xi  s
2 # Pe
# Pe
nkj
n
k 1
ki
; xi 
1
# Pv
n

#P
v k 1
kj
3
Experimental assessment
ESUR values for strictness measurement
HTML 4.01 Strict
( xi; xi)
XHTML 1.0 Strict
( xi; xi)
0.937 ; ~0.1
HTML 4.01
Frameset
HTML 4.01
Transitional
XHTML 1.0
Frameset
XHTML 1.0
Transitional
0.653 ; 0.103
~1.3 ; ~0.074
1.317 ; 0.130
Validity, strictness and Markup quality per geographical zones
Validity
Strictness
Markup quality
(real ; estimated)
(real ; estimated)
North
0.253
0.329 ; 0.272
1.038 ; 1.099
Centre
0.319
0.406 ; 0.401
0.951 ; 0.988
South
0.250
0.331 ; 0.301
1.046 ; 1.112
Islands
0.377
0.506 ; 0.480
1.148 ; 1.346
4