across groups. The two concepts have somewhat different historical roots and areas of application. Whereas bias usu-
ally refers to nuisance factors, equivalence has become the generic term for metrical implications of bias.
Bias and equivalence are not intrinsic properties of an instrument but arise in a group comparison with a par-
ticular instrument. An instrument that works well in the comparison of two groups may not work well when a
third country is involved. The literature on personality is dominated currently by the Five Factor Model (FFM, or
Big Five). It is claimed by adherents of the FFM that there is evidence from many cross-cultural studies that Big-
Five measures of personality show little bias (e.g., McCrae, Costa, Pilar, Rolland, & Parker, 1998 ;Schmitt, Allik,
McCrae, & Benet-Martı ´nez, 2007 ). Bias is more likely to affect comparisons of groups that differ in more test-
relevant aspects. So, notably when cross-cultural differences in countries or groups to be compared are large, bias
is more likely to emerge ( Van de Vijver & Leung, 1997 ).
Sources of Bias
There are three bias sources in cross-cultural personality research. The first is construct bias ; it occurs when the
construct measured is not identical across groups. Ho’s (1996) work on filial piety (psychological characteristics
associated with being a good son or daughter) provides a good example. The Western conceptualization is nar-
rower than the Chinese, according to which children are supposed to assume the role of caregiver to their parents
when these grow old and become needy. Construct bias precludes the cross-cultural measurement of a construct
with the same measure. An inventory of filial piety based on the Chinese conceptualization will cover aspects
unrelated to the concept among Western subjects, while a Western-based inventory will leave an important
Chinese aspect uncovered.
The second is method bias , which is used here as a label for bias emanating from factors often described in
the method section of empirical papers or study documentations. In cross-cultural studies these factors are
often confounded with culture; therefore, method bias sources often constitute alternative interpretations of
cross-cultural differences in target Variables. Examples of sources of method bias include incomparability of
samples (e.g., differences in education or motivation), differences in environmental administration conditions
(e.g., ambient noise), ambiguous instructions for respondents and/or guidelines for administrators, differential
expertise of administrators, tester/interviewer/observer effects (e.g., halo effects), communication problems
between respondent and interviewer, differential familiarity with stimulus materials (notably relevant in cogni-
tive testing), differential familiarity with response procedures, and differential response styles (e.g., social desir-
ability, extremity scoring, acquiescence). Some sources of method bias can be dealt with by careful preparation
of the assessment instrument and its instruction manual (e.g., proper test instruction with a clear specification
of what is asked from participants, standardization of administration, and adequate training of testers and
interviewers). Yet, in practice it is often impossible to eliminate all outcome-relevant sample characteristics, par-
ticularly when the cultural distance of the countries involved is large. There are indications that a country’s
Gross National Product (per capita) is negatively related to its mean score on acquiescence and social desirabil-
ity (Van Hemert, Van de Vijver, Poortinga, & Georgas, 2002 ). Particularly in comparisons of culturally highly
dissimilar groups it may be hard or even impossible to eliminate the impact of sources of method bias such as
test familiarity and social desirability.
Finally, bias can be due to anomalies at the item level (e.g., poor translations); this is called item bias or
Differential Item Functioning (DIF) . According to a widely used definition, an item is biased if persons with the
same standing on the underlying construct (e.g., equally intelligent) but coming from different cultural groups
do not have the same expected score on the item. The expected item score is usually derived from the total test
score. If a geography test administered to pupils in Poland and Japan contains the item ‘What is the capital of
Poland?’ the test would be said to be biased in favor of Polish students, who can be expected to show higher
scores on the item than Japanese students, even when pupils with the same total test score from the two countries
would be compared. The item is biased as it favors one cultural group across all test score levels. Of all bias
types, item bias has been the most extensively studied; various psychometric techniques are available to identify
item bias (e.g., Osterlind & Everson, 2010 ).
Types of Equivalence
Four different types of equivalence are proposed ( He & Van de Vijver, 2012; Johnson, 1998; Matsumoto & Van
de Vijver, 2011; Van de Vijver & Leung, 1997 ). The first is labeled construct inequivalence . Constructs are754 26. MEASURES OF PERSONALITY ACROSS CULTURES
VI. SOCIOCULTURAL INTERACTION AND CONFLICT