Furthermore, a moderate effect of SES on primary school students' ICT competences exists. More specifically, it seems that students
that have a mother with a degree of higher education have better developed technical ICT skills and higher-order ICT competences with
regard to digital communication and digital information searching and processing. In contrast to the gender related differences, the
effect of SES applies to almost all clusters of the developed framework. As such, this study provides evidence that SES is an important
factor for software developers and teachers to consider during the selection and development of digital tasks in which students can
develop their ICT competences. A possible reason for these SES related differences in ICT competences, can be found in specific types of
out of school ICT use of different socioeconomic groups. Volman et al. (2005) studied computer and Internet use from the perspective of
ethnic differences. These authors found that students from an ethnic-minority background use the computer at home more to practice
what they have learned at school (such as word processing and doing math), whereas students from a majority background use the
computer more to communicate and surf on the Internet. This effect is possibly even reinforced by the fact that the use of computers as a
learning tool and to learn basic ICT skills, receives higher priority in primary education as compared to using ICT as an information tool
(Tondeur, van Braak, & Valcke, 2007). Similarly, it can be expected that students from higher SES groups have more experience with the
ICT competences incorporated in this study's performance-based test i.e. digital communication and information processing. In this
context, Vekiri (2010) found that the percentage of high SES students that searches the Internet for information is higher than the
percentage of low SES students conducting this specific type of ICT activities. Future research could focus on this phenomenon by
investigating interaction effects between SES and specific types of ICT use on ICT competences. This research is of major importance, as
students' ICT use and ICT competences can make a difference in their academic related performances (Claro et al., 2012; OECD, 2010).
This means that SES related differences in ICT competences could also enlarge differences in academic related performance, and
eventually maintain socioeconomic differences.
A limitation of this study is the absence of testing measurement invariance before making the comparisons between gender and SES
groups. Although we found differences in ICT competences between SES groups, it is difficult to say whether these differences can be
attributed to characteristics of the SES group or characteristics of the test. As such, future research should investigate whether our test is
interpreted in a similar way in different groups before making comparisons between groups. For this purpose, the latent variables un-
derlying the items of our test should first be identified. Afterwards it should be checked whether the mathematical function that relates
these latent variables to the data is the same in each SES and gender group (Teo, 2014).
Although we consider it a strength of this study that a performance based measure of ICTcompetences was used, it is regrettable that the
investigation of the gender and SES differences was notexpanded to self-report measures of ICTcompetence or measures of ICTself-efficacy.
Future research should investigate whether the relationships identified in this study could be replicated using self-report measures. With
regard to the relationship between gender and ICT competences, the study of Tsai and Tsai (2010) provided results similar to those of this
study. More specifically, their study indicated a positive relationship between gender and students' self-reported online communication
competences in favor of girls, whereas our results indicate the same relationship using a performance-based rather than a self-report
measure of ICT competence. These similar results indicate that the relationships found between gender and actual ICT competences,
perhaps also will be found between gender and self-reported measures of ICTcompetence. However, the items in the study of Tsai and Tsai
(2010) are not based on the exact same construct that provided input for the development of the items in this study. As such, future research
should first develop self-reported and performance-based items that highly match, in order to investigate whether relationships identified
in the case of performance-based items, could also be replicated using self-report measures.
Another limitation of this study was the restriction of the number of ICT competences that were measured. As the performance-based
test only measured locating and processing digital information and digital communication, it did not address the measurement of other ICT
competences.