Student Friendship choices and Ethnic homophily in the
classroom
Amalia Alvarez1
1
Max Planck Institute for Research on Collective Goods
Abstract
The effect of ethnic homophily, i.e. the desire of agents to be connected to similar
others, is a persistent feature of, especially in the school context. In this study I use
two observations of the complete social network of a cohort of Swedish students
(n=115) in a secondary school and analyses the scope of ethnic homophily on
segregation and homogeneity, as well as the effect of structural factors such as
school's structural organization in classrooms.
Sociometric data was collected during a school year and the models presented are
based in crosscuts of the friendship network. Homophily in respect to ethnic origin is
found in both time points, with students making connections primarily within the
ethnic group. Nevertheless, the effect of ethnic homophily seems to decrease between
the waves, whereas the effect of structural constraints remains high over time. This
hypothesis, as well as the relevance of each effect, is then tested using both network
level measures and tie-based measures such as ERGM models. Results suggest that
organisational divisions in classrooms play a decisive role in the pattern of friendship
connections in the school. These boundaries should be taken into account when
conducting research on homophily in friendship networks in the school context.
Key words
Ethnic homophily, Friendship networks, Inter-ethnic friendship, School segregation,
School network
INTRODUCTION
A notable feature of social networks is their high degree of homogeneity. People who
are similar with respect to many different attributes, ranging from education, attitudes
or occupation, to social status, are more likely to be connected as friends,
acquaintances, or spouses, than are dissimilar people (e.g., Blau, 1977; Marsden, 1987,
1988; McPherson et al., 2001; Verbrugge, 1977). This happens in many contexts such
as school (Shrum, Cheek, & Hunter, 1988), work place (Ibarra, 1992) or couples
(Kalmijn, 1998, 1994). The preference for similar ones, in the absence of other
constraints, leads to individuals choosing their connections based on a similarity of
attributes, a phenomenon known as homophily.
The strength of homophily tendencies varies between attributes, with ethnic origin
being one of the strongest basis for homophily (McPherson et al., 2001). Thus, ethnic
segregation is a persistent feature of friendship networks in general, and in school
settings in particular (Joyner, 2000; Kandel, 1978; Kao & Joyner, 2004; Shrum et al.,
1988). This is a question of broad relevance: ties between the different ethnic groups
can reduce discrimination, decrease implicit and explicit ethnic bias, and increase
minorities’ access to social resources and information (Pettigrew & Tropp, 2000;
Pettigrew, Tropp, Wagner, & Christ, 2011).
Despite the importance of ethnic homophily friendship choices are not only dependent
on the attributes and preferences of the individuals making the choice, but they are also
influenced by the opportunity of contacts, Shared activities and organisational
structures have also been found to affect the patterns of friendships (Feld, 1981, 1982),
because the organisational structure might promote interaction among certain
individuals, thus influencing friendship choices in school (Moody, 2001), and
elsewhere.
The purpose of this study is to investigate students’ possible preference for ethnic
similarity that will result in a majority of friendships being intra-ethnic, and the effect
of the local structural organization of the school (i.e. school classrooms) that will lead
to students choosing to befriend others within their own classroom.
1
I first review previous theory and research on homophily. Based on this, different
hypotheses are proposed. The first two hypotheses explore the patterns of ethnic
segregation and homophily in the school in two different time points of the school year
and the effect of the opportunity structure. The third hypothesis examines the
possibility of interplay between ethnic homophily and constraints imposed by the
division of the school in classrooms. If the contact within classrooms fosters friendship
then, the effect of ethnic homophily should diminish over time, whereas the number of
friendship intra classroom should remain stable or increase. This would result in a less
segregated friendship network over time and a reduced effect of ethnicity in the
decision of forming a friendship.
THEORY AND HYPOTHESES
ETHNIC HOMOPHILY AND SCHOOL FRIENDSHIP CHOICES
Friendship homophily is defined as the selection of friends given a motivation to seek
similarity 1 . Homophily is, thus, induced by in-group bias and personal choice
(Kossinets & Watts, 2009; McPherson & Smith-Lovin, 1987, 2001). Ethnicity is one
of the most common attributes defining similarity and group membership (McGuire &
McGuire, 1978) which throughout individuals construct their social identity
(Baumeister & Leary, 1995; Tajfel, 1974; 1978; Turner, 1975) and set the basis for
social interactions. In the presence of homophily, individuals create most of their
connection within their in-group2 (e.g., Girvan & Newman, 2002; Henry, Prałat, &
Zhang, 2011; Palla, Barabási, & Vicsek, 2007; Watts, Dodds, & Newman, 2002). The
reasons for this tendency are diverse: individuals seem to be attracted to similar ones
(Byrne, 1961) or interaction with similar people might be easier due to shared
knowledge and culture (Kalmijn, 1994). In the case of ethnic homophily, for example,
1As the preferred interaction between individuals who share membership in a social category (Wimmer
& Lewis, 2010), homophily is a sort of in-group preference (Blau, 1977), and we should think about it as
cognitive process, i.e. it refers to ego’s beliefs. Therefore choice homophily is (incorrectly or correctly)
based on ego’s beliefs about alter’s attributes.
2
Group membership not only increases the probability of a connection, it might influence in-group
favoritism, pro-social behavior, like altruistic cooperation and norm enforcement (Goette et al., 2012;
Nowak, 2006; Ostrom & Sedikides, 1992).
2
different mechanisms could play a role in the preference for intra-ethnic ties such as
within group similarities derived from a similar cultural background, similar language,
and similar status or prejudice. From a rational choice perspective, what derives is that
establishing a friendship outside one’s ethnic group is costly, in comparison with
befriending people from the in-group (Currarini and Vega-Redondo, 2009; Currarini et
al., 2013).
Empirical research has found a high preference for ethnic similarity in friendship
choices in different social contexts (Wade & Okesola, 2002) and following different
ethnic classification3 (Kao & Joyner, 200, 2004). In the school context researchers
have systematically found significant evidence of homophily between black and whites
in the schools (e.g., DuBois & Hirsch, 1990; Hallinan & Williams, 1989; Kao &
Joyner, 2000, 2004; Shrum, Cheek, & Hunter, 1988). However, in recent years the
field has been enlarged with the incorporation of new categories such as Hispanic and
Asian backgrounds (Carlson, Wilson, & Hargrave, 2003; Iceland, 2004; Quillian &
Campbell, 2003). Studies found persistent high levels of segregation of blacks,
including black Hispanics (i.e. Afro-Latin), from all other ethnic groups (Quillian &
Campbell, 2003).
Research conducted in Europe shows a preference for intra-ethnic friendship in native
students in Germany (Titzmann & Silbereisen, 2009) , as well as for European students
in The Netherlands, Sweden and Germany (Smith, Maas, & van Tubergen, 2014).
Adolescents from the three countries were found to nominate ethnic in-group peers as
friends. Natives were found to persistently show a strong ethnic in-group preference,
whereas, some other ethnic groups were not, such as people with Lebanese origin in
Sweden (Smith et al., 2014).
Ethnic homophily might provide individuals with several advantages, such as increased
mutual support, reduced communication cost or increased reciprocity and cooperation
(Barros, 2007; Nowak, 2006). Nonetheless, homophily can lead to group conflict and
or perpetual inequality (DiMaggio & Garip, 2011, 2012; Ibarra, 1992) by different
mechanisms. First, it can lead to higher levels of prejudice and rigid in-group/outgroup delimitations, what prevents social identification outside the in-group and affect
3
In this study the ethnic classification is based on the student’s parents country of origin.
3
students’ ethnic and racial attitudes4 (Tajfel, 1978; Ellison & Powers, 1994; Emerson,
Kimbro & Yancey, 2002). Conversely, ties across different ethnic groups can reduce
prejudice (Allport, 1954; Pettigrew & Tropp, 2000). In the school context, an increased
level of prejudice might lead to a higher level of exclusion affecting, among others,
students’ academic achievement (Kao & Tienda 1998; Kao & Johnson, 2003), and
intensifying school violence (Juvonen, Nishina, & Graham, 2000; Graham & Juvonen,
2002). Furthermore, the patterns of ethnic friendship may be indicative of social
distance between ethnic groups in the future (Joyner & Kao, 2004). As thi pattern
persists over time, homophily might lead to unequal and differential access and return
of social capital (Lin, 1999, 2000; Portes, 1998), therefore perpetuating inequality.
Hence, ethnic homophily might be seen as a mechanism for the persistence of
inequalities or disadvantages of groups (DiMaggio & Garip, 2011, 2012; Lin, 2000)
and has been widely discussed for both migrant and ethnic/racial status (Lin & Dumin,
1986; Lin, 2004), also in Sweden (Behtoui, 2006; Rydgren, 2004)
FRIENDSHIP CHOICES AND OPPORTUNITY STRUCTURE
The importance of homophilous preferences in shaping friendship choices is
unquestionable, yet not the only force at play. Past research has shown that friendship
choices also depend on opportunity structure. Indeed the number of ties between
structurally distant individuals is normally small because people befriend others that
they have the opportunity to meet, thus, preferences for similarity are expected to be
“expressed in the absence of other reasons to form new ties” (Kossinets & Watts, 2009,
p. 436) such as proximity and repeated interaction.
The two mechanisms are not mutually exclusive, but they rather interact. Structural
determinants might intensify or lessen the effect of individual preferences. In the case
of ethnic homophily, for instance, past research concluded that shared activities
increase the likelihood of inter-ethnic ties (Kao & Joyner, 2004), and other findings
suggest that interethnic friendship must be promoted by groups of common interests
(Stark & Flache, 2011), and by the constraints to the meeting opportunity (Blau, 1977;
Feld, 1981, 1982). The divisions in classrooms creates an structure that forces people
4For
instance, adolescents within the same group report similar levels of prejudice towards stigmatized
ethnic minorities (Kiesner, Maass, Cadinu, & Vallese, 2003)
4
to interact, which in turn would reduce prejudice and reduce ethnic segregation and
homophilly, i.e. Contact hypothesis (Allport, 1954). Then, choice homophily as a
mechanism of friendship formation might have a stronger impact where there are no
other constraints that facilitate interaction, as the organisation of students in
classrooms.
THE PRESENT RESEARCH
In this study I present some particularities of special interest for the research of ethnic
homophily in school settings while trying to overcome past limitations. The models are
constructed using data from second-generation immigrant or immigrants with a long
history in the country, thus avoiding biases due to the different stages of the
acculturation process of the individuals. Also, I introduce a ethnic classification that
considers national and cultural links based in wider national and cultural categories, in
the line of newest research such as Smith et al., (2014). This classification tries to be
more encompassing than previous categories such as natives and non-natives or racial
categories. Past research has mainly focused in participation in interest-based groups
and associations, whereas exogenously imposed structural subdivisions, like
classrooms, have remained mostly understudied. The case at hand represents a very
good opportunity to investigate the interplay between the structure of opportunities and
choice homophily.
Finally, the small school setting (n=115 students) allows for network and group level
techniques, as well as tie-based analysis, without the necessity of extremely powerful
computation techniques. Complicated techniques have been a major reason for using
group-based measures even though individual-level measures are known to be better
(Zeng & Xie, 2008). In this study both network level measures as well as tie-based,
exponential random graph models (ERGM), are used to investigate ethnic segregation
and ethnic homophily.
HYPOTHESES
Based on previous findings and theory I expect students in the school might display a
preference to be linked to similar ethnic ones, therefore resulting in a homophilous
5
network in respect to ethnic group, as well as ethnic segregation. However friendship
choices might be affected by constraints imposed by the structure, as the division in
classrooms in the school. Hence, the research will analyse two different determinants
of friendship choices in the school: student’s possible motivations to seek ethnic
similarity and its interrelation with homophily induced by structural organization. The
first hypothesis tests whether students in the school display a tendency to befriend
individuals from their own ethnic group, as expected by results in past research.
Hypothesis 1: Similarity with respect to ethnic origin will breed connection in the
school resulting in ethnic segregation in the friendship network.
Hypothesis 2: Students tend to establish friendship within classrooms at all times.
Hypothesis 3: The effect of ethnic homophily in tie formation and ethnic segregation
diminishes between waves.
DATA AND METHODS
DATA
Data was collected from an upper secondary school (grades 10-12) located in one of
Sweden’s most populated urban areas. It comprises the complete friendship network of
students that started grade 10 in 2012, with a total of 115 individuals. Data were
collected5 by means of a survey during the scholar year 2012/13. I exploited two waves
of data. Wave 1 was collected in October at the beginning of the school year (October)
and wave 2 was collected in May at the end of the school year. Between the two times
of data collection the student composition of school changes, with some new students
coming and others quitting the school. The questionnaire included a roster to nominate
friends, as well as sociodemographic information about the students such as sex,
religion or parent’s country of birth. In the roster students could select with “whom
they hang out after school”. Following this data information on the full friendship
network was obtained. The school is divided into 4 classes with similar number of
5
Data was collected by Sara Roman who at that time was a PhD candidate and researcher at Stockholm
University. Data was collected with the purpose of serving for her own research.
6
students.
Table 1. Number of students by class and wave
Class
1
2
3
4
Total
Number students
Wave 1
Wave 2
27
28
25
19
27
24
24
25
103
96
Not in sample
Wave 1
Wave 2
2
3
1
1
0
4
2
1
5
9
The total number of students included is 103 in wave one and 96 in wave two. Five
students have not joined the school in the first wave and 9 have left before the second
wave. Some students were missing at time of data collection or did not want to
participate. Missing rate is 2,7% in wave 1 and 18% in wave two. Notice that contrary
to the students that were not present in the sample, missing students can still be
nominates as friends. Attribute-based missing information is very low. There is no
missing information in ethnicity or sex, and missing information about religion is
0.04%.
VARIABLE CONSTRUCTION
Friendship definition - A friendship is said to occur between two students, e.g., i and j,
when either j refers i as a friend or vice versa. Because most of the students did not
know each other from before we can assume that initial links are not the result of past
relationships. The network is directed and only some of the links are.
Ethnicity - The country of origin of the parents was used to determine the ethnic origin
of the students so the definition of ethnicity used in this study refers to national origin.
The classification is as follows: (1) students whose parents were born in Africa (subSaharan and horn of Africa) were classified as of African origin; (2) students with
parents born in a country part of the Middle East6 were classified as having middle east
ethnic background; (3) students whose parents were born in Europe7 were classified as
of European background, and finally; (4) a last category was created for students who
6
7
Middle East countries include: Iran, Irak, Egypt, and Kurdistan.
European countries include: Sweden, Iceland, Finland, France, Spain, Poland, and Bosnia.
7
could not be classified8. The frequencies of the groups in the two waves are shown in
Table 2.
Table 2. Number of students by ethnic origin
Ethnic background
Wave 1
Wave 2
Africa
EU
Middle East
Other
Total
31 (30.1%)
39 (37.9%)
21 (20.4%
12 11.7%)
103
32 (33.3%)
32 (33.3%)
21 (22.0%)
11 (11.5%)
96
The classification was done following the country of origin of the mother. In case of
missing information (0.017%) the country of birth of the father was used. All
ethnicities are present in all the classrooms in a sufficient amount for homophily to be
possible.
ANALYTICAL STRATEGY
In order to measure the network level homogeneity I used the EI index9. The E-I index
measures homogeneity (or segregation) in a network composed by mutually excluded
groups (e.g. the different ethnic origin groups). This measure compares the relative
density of internal connections within a group and the number of connections this
group has to others groups. The index is computed as the number of ties external to the
group minus the number of internal ties, and then divided by the total number of ties in
the network.
The value of the index ranges from 1 to -1 (being 1 totally heterophilous and -1 totally
homophilous). Nevertheless, as recommended in past research (Everett, 2012;
Krackhardt, 1988), it is often helpful to substrate the ratio from 1. The new ratio is
used in the graphs and its values range from 0 to 2, where 0 means total heterophily
and 2 total homophily. The index was implemented using the software UCINET
(Borgatti, 2002, 2013). The significance of the network level index can be tested using
8
Unclassified students are students with born within categories with less than three members. This last
group is less informative than the specific categories and, therefore, has been reduced as much as
possible.
9
The formula of the EI index is as follows:
𝐸−𝐼
𝐸𝐼 𝑖𝑛𝑑𝑒𝑥 =
𝐸+𝐼
8
a permutation test. The test provides a rescaled value of the whole network index that
control for density and group sizes. Because the permutation test gives a re-scaled
value that is invariant to size and density, the whole network level E-I index is
comparable between the two networks since it is not affected by group sizes.
To measure the effect of ethnic homophily in tie formation I build an ERGM model
that accounts for individual ethnic attributes, opportunity structure, and relational
mechanisms. ERG models allow us to consider in-group preferences for all the ethnic
groups while taking into account the effects of relative group size, structural effects
and network effects such as triadic closure and reciprocity simultaneously. The ERGM
models control for structural effects and capture relational mechanisms, thus allowing
to disentangling the effect of ethnic homophily from other possible mechanisms.
ERGM specifications. I used a model specification that accounts for the possible
network effects that can influence friendship choices. The term for triadic closure, i.e.
the tendency to befriend the friend of a friend, is the “geometrically weighted edgewise shared partner”10 (GWESP) statistic that can accommodate the often observed
tendency of two nodes to share more than one partner, thus controlling for clusters in
the network. A term for reciprocity, i.e. the tendency of two students to nominate each
other, is also added to the model.
ERGM models can account for the relative sized of groups, but they cannot control for
the number of ties or how sociable a group is. In order to control for that sociability
term has been added for every ethnic group. This term controls for the total number of
ties of each group. A homophily term is added to the model for each of the ethnic
groups, as well as for classroom and sex. The homophily terms are dyadic covariates
that take the value of 1 if both nodes belong to the same group and 0 otherwise.
RESULTS
WITHIN CLASSROOMS FRIENDSHIPS
The majority of friendships are made within the classroom: 80% of the ties come from
the same classroom in wave 1, whereas only 73% of the ties are created within
10The geometrical weight expresses the expectation that higher-order triangles are less likely than lower
order triangles.
9
classrooms in wave 2 (see table 3). The empirical results are in line with the hypothesis
that most of friendships are made within classroom, although, the effect seems to
decrease between the waves. The test for intra-classroom friendship choices shows a
re-scaled E-I index of 1.551 (p.05 SD=.057) compared to an expected value of 0.487.
This means that the majority of nominated friends of a student come from the same
classroom making the network segregated by classrooms.
The effect of classroom persists in wave 2. The re-scaled E-I index for classrooms has
a significant value of 1.439 (p < .05; SD=.053), very similar to the value in wave 1.
This confirms that the effect of organisation in classrooms remains high across waves,
with a majority of friendships coming from the own classroom and that the
organisation in classrooms exerts an important effect in the patterns of friendship.
Table 3. Descriptive network measures
Density11
Wave 1
Wave 2
0.026
0.031
Network attributes
N. of ties
Avg. degree
270
285
5.24
5.94
w/i classroom ties
216 (80%)
208 (73%)
E-I INDEX AND SEGREGATION MEASURE
If hypothesis 1 is correct, and similarity with respect to ethnic origin leads to
connection in the school network, then we should expect a bigger number of links
within the in-groups than between groups. This will translates into a significant and
larger than 1 E-I index. In wave 1 the E-I index computed for the whole network takes
a value of 1.05 (p<.05 SD=.065), indicating the presence of homophily in the network.
The expected value for the E-I index is 0.565, so the current value for the index
considerably deviates from expected from the baseline ethnic composition of the
school population. In order to test whether this deviation is statistically significant, a
permutation test was computed. The permutation test (Table 4) with 10000 iterations
shows that the homophily found by the E-I index is significant at the 95% level. This
means that, with a 95% of times, the E-I of the network do not fall in the random
11
Density of the network is defined as the ratio of the observed number of ties to the number of possible
ties.
10
distribution provided by the permutation test. The results ensure that the distribution of
ties given the groups significantly differs from random. It suggests that the level of
homophily of the network is significantly higher than expected if the connections were
done by chance or if the divisions into ethnic groups did not play a role.
Table 4. Permutation test E-I index wave 1
Internal
External
E-I
Obs
0.502
0.498
-0.05
Min
0.161
0.576
0.151
Avg
0.282
0.718
0.435
Max
0.424
0.839
0.678
SD
0.033
0.033
0.065
P>= Ob
0.000
1.000
1.000
P<= Ob
1.000
0.000
0.000
Note- Number of iterations = 10000. E-I Index is significant (p < .05)
The network in wave 3 does not show signs of ethnic segregation. The E-I Index for
the whole network in wave 2 takes a value of 0.892 (SD=.060). The permutation test
shows that the index is not statistically significant, even though it is somewhat bigger
than the expected value. Thus, results suggest that the network in wave 2 is no longer
segregated with respect to ethnic origin or that, at least, results do not vary
significantly from random. Results suggest that ethnic homophily exerts a greater
effect at the beginning of the scholar year, but this effect diminishes over time.
ERGM MODEL
The empirical results presented until now allow us to measure segregation at a network
level. In this section, I present an ERGM model (table 5) to investigate the sources of
tie formation.
11
Table 5. ERGM model results
DEPENDENT VARIABLE
WAVE 1
WAVE 2
Edges…………………….
-5.511*** (0.225)
-5.212*** (0.209)
Triadic closure (GWESP).
1.339*** (0.129)
1.472*** (0.117)
Reciprocity………………
2.080*** (0.256)
0.538** (0.266)
Sex……………………….
0.641*** (0.111)
0.560*** (0.103)
Classroom………………..
1.297*** (0.133)
1.210*** (0.112)
Africa..…………………..
-0.161 (0.127)
-0.158 (0.129)
EU……………………….
-0.366** (0.144)
-0.157 (0.138)
Middle East………………
-0.223 (0.140)
-0.159 (0.135)
Africa..…………………..
0.409* (0.225)
0.398* (0.229)
EU……………………….
0.788*** (0.216)
0.525** (0.234)
Middle East……………...
0.726*** (0.257)
0.669** (0.269)
Network terms
Sociality terms
Ethnic homophily terms
AIC…………………………
BIC…………………………
Note-
1,631.661
1,718.777
1,887.457
1,972.876
*p<0.1; **p<0.05; ***p<0.01
The terms for network-specific effects, number of edges, triadic closure and
reciprocity, are all significant predictors of tie formation in both waves, and the p-value
is far less than the conventional significance level of .05 cut off. The coefficients in
table 5 are expressed as conditional log-odds. The parameter for edges indicates the
baseline random probability of tie formation if the other model elements are ignored.
Thus, the log-odds of a tie being created are -5.511 in wave 1, which yields a
probability of 0.004 of forming a tie in the network, and -5.212 in wave 2, with a 0.005
probability12. The log-odds that a within classroom friendship will form equals 1.297
in wave 1 and 1.210 in wave 2, which yield probabilities of 0.015 and 0.018
respectively. Likewise, the probability of an ethnic homophilous tie in wave 1 equals
12
p= exp(β)/(1+exp(β)).
12
0.009 for the EU group, 0.006 for students of African origin and 0.0083 for students of
the Middle East group. In wave 2 these probabilities are 0.008 for African, 0.0091 for
EU and 0.010 for students from Middle East.
The probabilities of tie formation are higher in wave 2 for all the terms because the
baseline probability of tie formation is higher in wave 2. This is consistent with the
descriptive statistics of the network in both waves that show an increase in the average
degree and density of the network. Nevertheless in order to compare the effect of the
homophily and classroom terms in both waves we should look at the magnitude of the
coefficients. The coefficients of the homophily terms are smaller in wave 2 than in
wave 1. These results are in line with the proposed hypothesis that the effect of ethnic
homophily in tie formation will decrease between the waves. Nonetheless the effect of
being in the same classroom also decreases in wave 2.
The results above show that on the one hand the ethnic segregation decreases over time
and the global effect of the divisions in classrooms remains. On the other hand the
preference for ethnic similarity, albeit less pronounced in wave 2, influences tie
formation in both waves.
DISCUSSION
The main objective of this research was to study ethnic segregation and tie formation
between different ethnic groups in the Swedish school context and the effect of
organisation of the context in classrooms. Results of ethnic homophily at the networklevel and also at the tie level have been presented in this study. The main findings are:
1) using parent’s country of birth as a proxy for ethnic group, the network presents
ethnic segregation, but it decreases between the waves, 2) ethnic homophily affects
friendship nomination, although the effect seems to decrease over time, and 3) there is
a strong tendency to make friendships within the own classroom in both waves, as the
second hypothesis predicted. Results from network level measures seem to be in the
line with hypotheses one and two discussed earlier in the study.
Concerning ethnic homophily the study produced some valuable results. The ERGM
model shows that ethnic homophily influences friendship choices at all times in the
school. In line with previous research students in the school select friends that are
13
ethnic similar to them. Results differ across ethnic backgrounds with groups displaying
slightly different patterns of homophily. In the case of this study the picture might be
more complicated to interpret because the categories encompass various countries of
origin. The findings suggest that ethnicity might be less of a barrier to students with
African origin than to European or Middle East backgrounds.
A question posed by the interpretation of the homophily induced by the organisational
structure, i.e. the classrooms, is whether the organisational foci exert stronger effect on
the patterns of friendship in the school than a individual preference for ethnic group.
Results suggest that, due to its salience as a social cue, ethnicity seems to guide
friendship nominations, but the patterns of friendship in the school are affected by the
organisation in classrooms as well as other network effects, because the effect of ethnic
homophily decreases over time whilst the effect of the context remains very strong at
all times. A first, intuitive explanation13 and that the findings in the study seem to
support is that the organisation in classrooms might serve as a constrained opportunity
structure. Classroom creates the social boundaries within individuals are supposed to
establish their social relationship and delimit who can be selected as a friend by
increasing the meeting opportunities of members of the same classroom. One of the
most important conclusions of this study is that is the classroom and not the grade or
the school the real boundaries for friendship making, and this has to be taken into
account in future research. However, to test whether the shared environment and the
repeated interaction within classrooms enhance the likelihood of friendship between
students from different ethnicities, further research is needed.
In concluding, I argue that results in this case study imply that within small schools,
organisation in classrooms is a stronger predictor of connections than ethnic traits,
what means that organisation of the context could bring dissimilar people into contact.
The context serves as a base for expression of preferences. If the context from which
friends are chosen is homogeneous, there will be high levels of ethnic homogeneity,
however, in ethnic diverse settings, the context promotes inter-ethnic friendships.
Factors such as cooperation and increased contact have been found to diminish ethnic
13
From a more economic perspective we can think that creating a new connection is a costly action,
people might perceive an incurred cost on creating a connection with someone from a different class. In
this sense individuals might just adapt to the context with a cost benefit analysis of friendship formation
and will seek similarity only when it is cost-effective (Currarini & Vega-Redondo, 2013; Currarini et al.,
2009).
14
prejudice and promote inter-ethnic friendships (Allport, 1979; Weigel, Wiser, & Cook,
1975). Even though results in the case at hand cannot ensure that student’s preferences
in respect to ethnic similarity changed, the findings suggest that, at least, the network is
not ethnically segregated in wave 2. To some extent results can inform policies aimed
to decreased ethnic segregation, by bearing in mind that certain context organisations
might encourage inter-ethnic friendship. The study also has some implications for
future research in ethnic homophily in schools. Findings in this study suggest that
classrooms might be always taken into account in the study of homophily in the school,
since this organisation of the context represents the boundaries in which friendship are
created.
15
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