Selection of Participating Schools

Participants were girls in school years 9 and 10 at both mixed and single-sex secondary schools. No single sex boys’ schools were selected, but boys attending the same mixed classes as the girls were asked to take part as this was most convenient for the schools involved. The research presented here is based on data from the girls only.

Initially, it was planned that all data collection would take place within the Wirral Education Authority. This LEA was selected as it serves pupils from a wide range of socio-economic backgrounds. Wirral includes both the socially disadvantaged communities of Birkenhead and Wallasey and the considerably more affluent Bebington and Deeside. There were 7 girls' and 12 mixed state secondary schools in Wirral. A large independent girls school within the same geographical area was also included in the sampling frame, although two very small mixed independent schools (<30 pupils/year) were omitted.

Chapter 4. Baseline methodology and descriptive statistics

One disadvantage of the Wirral area, which emerged during the sampling, was that mixed schools were disproportionately represented amongst the schools in more deprived areas, whilst all of the high SES schools were single sex. This presented problems as it could confound the effects o f SES with those of attendance at a single sex school. For this reason the population o f schools was extended into the western part o f the adjoining Cheshire LEA (Ellesmere Port and Vale Royal areas). This added a further 7 mixed schools to the sample, producing a population of 26 girls and mixed sex secondary schools.

4.1.2.1 Free school meals as a school-level marker of deprivation

A useful measure of deprivation at a school level, which was available as a proxy for the overall socio-economic backgrounds o f pupils at the schools, is the percentage of pupils at each school that are eligible for free school meals (FSM). This benefit is available to pupils whose family income is low. In the 26 schools FSM eligibility varied from 3.4 to 61.1 percent. In order to ensure that the sample included pupils from a wide range of socio-economic backgrounds, schools were classified into high, medium and low SES according to the percentage of pupils in receipt o f free school meals. As information on FSM was not available for the independent school, it was included in the high affluence group. The numbers of girls and mixed schools falling into each of the affluence categories is shown in table 4.1.

Table 4.1 Schools in the high, medium and low affluence groups

School Affluence Level Wirral

Mixed Girls

Cheshire Mixed Girls

High (<10% Free school meals) 0 4 3 0

Medium (10-25% Free school meals) 2 2 2 0

Low (>25% Free school meals) 10 1 2 0

Two schools were randomly selected from each of the high, medium and low affluence categories, a girls school and a mixed school at each level. This produced the final sample of six schools. The selected schools had a total of

Chapter 4. Baseline methodology and descriptive statistics

1434 girls registered in the participating year groups. The percentage o f pupils eligible to receive free school meals at each of the six schools are indicated in table 4.2.

Table 4.2 Pupils eligible to receive free school meals (FSM) at each participating school

School Afflluence level School type % FSM

High Girls (Independent)

Mixed 4 Medium Girls 13 Mixed 21 Low Mixed 34 Girls 42 4.1.3 Procedure

Ethical approval for the project was obtained from the joint UCL / UCLH Committee on the Ethics of Human Research in the Spring o f 1999 (Appendix B). Headteachers of the selected schools were contacted in May o f the same year. They were provided with details of the project, and asked whether their school would be able to take part. Schools were offered a £100 contribution to their libraries in return for their participation. All the headteachers contacted agreed to participate, and arranged for the involvement of all year 9 and 10 pupils.

Baseline data collection took place during the Autumn term 1999. Data were collected from pupils during class sessions, by trained researchers. Prior to the school visits pupils received an information sheet explaining aims and methods of the project (Appendix C), which they were asked to take home to their parents. They also received an opt-out form, which parents could return to the school if they did not wish their child to participate in the study. At the start of each class session the study was explained to pupils again. They were informed that participation in the project was voluntary and that even if they did take part

Chapter 4. Baseline methodology and descriptive statistics

they were not obliged to answer any questions or take part in any procedures which were upsetting to them. Pupils were also assured that their responses would be kept entirely confidential. Pupils who agreed to take part then completed a consent form (Appendix D). A pupil’s name and date of birth were written on the consent form, which was linked to their questionnaire with a unique number. The consent form and questionnaire were then separated. This ensured the confidentiality of responses, but also allowed for the linking o f an individual’s questionnaires at follow-up. Any pupils who were not participating were told that they could get on with other work or fill in a puzzle sheet provided. In some cases pupils who did not wish to participate had been dismissed from the classroom before the researchers arrived, and in those cases teachers were asked how many girls had opted out.

Class sessions were between fifty minutes and one and a half hours. Participants were asked to work through the questionnaire on their own, but were told that they were free to ask any questions. Whilst they worked, the researcher set up the height and weight measuring equipment in a nearby location out of sight of the class. Pupils were taken out of the class one at a time to have their height and weight measured. All measurements were taken with shoes and outdoor clothing removed. Measurements were recorded on the consent form, which was not returned to the child in order to ensure privacy, although a participant's own measurements were provided to that participant when requested.

4.1.3.1 Participation levels

Useable data were obtained from 1177 girls, which represented 82% of the female pupils registered in the relevant year groups of the schools in the sample. The majority o f cases of non-participation were a result o f pupils being absent from class on the day of the data collection. Reasons for this included authorised and unauthorised absence from school, and attendance at special lessons. Only a very small proportion of non-participation was due to parental or pupil refusal to take part. The breakdown of non-participation is given in Table 4.3.

Chapter 4. Baseline methodology and descriptive statistics

Table 4.3 Breakdown of non-participation

N %

Useable data 1177 82.1

Very incomplete or spoiled data 2 0.1

Parental refusals 17 1.2

Pupil refusals 6 0.4

Absent from class 232 16.2

Total (Girls registered in years 9 and 10 o f selected schools) 1434 100

4.2 Measures

The following sections give details o f all scales and measures. Full versions in the order and format in which they were presented to participants can be found in appendix E.