Description of method to establish a representative sample of PIPS data for Scotland and a stable cohort for trend analysis
Representativeness of the 2012/13 Scottish cohort
Those schools using PIPS completed background data for each pupil within the assessment when they started school in Primary 1 aged between four and a half and five and a half. This included home postcode and Scottish Candidate Number (SCN). Either of these measures can be used to allocate a pupil to one of the deciles linked to the Scottish Index of Multiple Deprivation (SIMD). However, the assessment can be carried out without these details being completed and for the assessments administered in the 2012/13 academic year, the following information was available:
Number of pupils assessed: 20,775
Number of valid pupil postcodes: 6,519
Number of valid Scottish candidate IDs: 9,991
Number of pupils with either a valid postcode or SCID or both: 12,123
Figure 1 shows the distribution of pupils in Primary 1 by Scottish Index of Multiple Deprivation (SIMD 2012) decile from data supplied by the Scottish Government Educational Analytical Services Division. 335 pupils with unknown data zone are not included.
This distribution can be compared with the distribution of pupils in the PIPS dataset based only on postcode information.
The distribution of the number of pupils in the PIPS data set for whom home postcodes were available was fairly even across the deciles. The proportions were close to the full dataset with slightly fewer than expected for some groups (Deciles 1, 2 and 10).
The distribution of the number of pupils in the PIPS data set for whom SCNs were available was also fairly even across the deciles. The proportions were close to the full dataset with slightly fewer than expected for some groups (deciles 1, 6, 7 and 10).
For 4,275 pupils, deciles were available which were derived from a postcode and SCN. The vast majority of these deciles were identical but in some cases they were not. The two sets of deciles were combined and, where there was conflict, the decile derived from the SCN was preferred. The resultant deciles derived from both postcodes and SCN are shown below in Figure 4.
A proportional random sample of pupils in each decile from PIPS data was selected to give a representative sample of the National Dataset as supplied by the Scottish Government's Education Analytical Services. This is reported in Figure 5. This sample was used for further investigation.
Email: Wendy van der Neut