Sex differences in social networks 8
schools, parents of the children involved in the study as well as from the university ethics
committee. The four classes constituted a sample size of 126 pupils at T1 (59 boys and 67 girls) and
122 pupils at T2 (55 boys and 67 girls). Between time points, 6 boys and 1 girl left and 2 boys and 1
girl entered the classes studied resulting in 119 children present at both time points. Two classes had
approximately equal numbers of boys and girls, one class had a majority of girls (65%) and the
other had a majority of boys (73%). Schools were located in low to middle socioeconomic status
areas. Three schools had a broad mix of children from different ethnic backgrounds (16% black
African/Caribbean, 16% west Asian, 2% east Asian, 53% UK white, 9% European white and 3%
other). The fourth school was almost exclusively UK white.
Data Collection
A male and female researcher, both UK white and aged 28-30, spent two weeks in each
school at both time points observing pupils on the playground and conducting structured interviews.
To facilitate easy identification of pupils and to get students used to their presence, researchers sat
in class and observed children undertaking their work. Children were given opportunities to
question the researchers in the classroom, but not the playground. Every effort was made by the
researchers to avoid being perceived as an authority figure or part of the school establishment.
These steps facilitated unobtrusive observation of pupils on the playground.
Observations of playground behaviour.
Pupils were observed on the playground using a systematic scan sampling technique based
on previous research (e.g. Boulton, 1992; Ladd & Price, 1993). Scan observations of pupils in each
class were conducted for the duration of every playtime (approx. 1½ hours per day) over the two
week period. Once the target child was located on the playground, they were observed for 20
seconds and then their behavioural interactions were coded, using pre-selected categories, via
commentary into a tape recorder with a hidden microphone. The 20 seconds of observation prior to