Aims: To develop an anonymisation policy for ALSPAC to be implemented for use of any release which may include linked NHS data. The policy needs to be submitted with the application of the Information Goverance Toolkit which needs to be in place to continue receiving and gaining further section 251 support. Further to this policy, we aim to explore anonymisation techniques determining the most secure level of anonymisation with the least effect upon the quality of the data for research. Using previous research on datasets which have been anoymised to different levels and using different techniques.

The anonymisation policy, for the IG Toolkit, will need to include the minimum level of anonymisation needed for release files of linked NHS data, k-anonymisation on quasi-identifiers.

Hyptheses: To determine the most secure method of anonymisation with the least impact on the quality of the data for research.

The hypotheses will be explored using a previous research question published by Kate Northstone. The research used to test the impact is as follows:

Maternal fish intake and child dietary patterns and associations with educational outcome at 16 years of age.

Outcomes: Child achieved 5 or more GCSE's at grade C or above, including maths and english.

Primary exposures:

1) Fish intake during pregnancy (none, 1-340g and greater than 340g)

2) Omega-3 intake (none, any actual intake split into tertiles)

3) Child Dietary patterns derived from PCA at 3,4,7,9 and 13 years of age

Confounders:

Gender

Maternal age

Maternal education

Housing

Maternal life events

Birthweight

Gestation

Maternal Smoking

Parity

Maternal and paternal occupation

IMD

Geography.