Koot shows the differences in behavioral characteristics between clique members and non-clique members in early elementary school, the stability of clique membership and whether the differences in these characteristics are gender oriented. Three hundred first-grade students (151 boys, 149 girls) from eleven different elementary schools in the Netherlands participated. The children were examined by being asked to determine their best friends. This friendship was considered valid if the elected friendship was reciprocated by the other child. The child was considered to be in a clique when the following criteria were met 1) a clique consisted of at least three children 2) each child had to have more connections with members than non-members and 3) a link had to occur between all members of clique. Children were then rated by their peers to determine who was liked the most versus who was liked the least. The children were also asked to determine behavioural characteristics of participants and who best fit the description of characteristics such as aggressive, anxious, etc. The peer study was followed through every spring and children were given a small reward for their involvement. These results were then used to compare between clique members and non-clique members. These results were also used to discuss the children's characteristics while also separating based on gender. In first grade, 29 cliques were found with an average of 5.3 members. In second grade 25 cliques were found with an average of 6.2 members. This study suggests that clique members tend to be more adjusted and that gender may have some form of influence on the results. This study showed that isolated girls would have more behavioural problems than isolated boys. Effect of cliques on the development of psychopathology in children Researches have often conducted studies to determine whether membership to a clique produces positive or negative development. In one 4-year study of 451 children from age nine to twelve, Miranda Witvliet along with Pol A. C. van Lier, Mara Brendgen, Hans M. Koot, and Frank Vitaro examined longitudinal associations between clique membership status and internalizing and externalizing problems during late childhood. In this quasi-experiment the researchers aimed to discover if clique membership status was linked to increases in children's psychopathology. Children from five different elementary schools in northwestern Quebec, Canada were the participants of this particular study. In the study, clique membership status was identified through social network analysis, and peer nominations