Parent/carer email about postcodes

What precautions do you take to make sure an individual cannot be identified from their postcode?

There are general precautions about the security of our servers which I am sure every good business would adopt, but we make a special effort with postcodes.

I don't know if your child competed the survey online or on paper - the account to be given in each case is slightly different.

Online, the postcodes are encrypted using GnuPG when storing, and downloaded with the encryption intact (screenshot). 

Screenshot 2014-07-30 16.28.29.png

They are decrypted only when the postcode information is required; the decrypted postcode is not stored but discarded once the analysis is complete. The encryption is AES-256, which we believe has never been cracked, even when Government and Police are very keen to see what is on a suspect's computer.

For paper surveys, we store only part of the postcode with the case, replacing the last two letters with "99", like this:

SCHID PUPILID SEX AGE YEAR PCODE Q1 Q2 etc
712 1 0 12 8 9999999 1 0
712 2 0 13 8 SG19399 0 1
712 3 1 13 8 SG19299 0 1
712 4 0 13 8 SG19399 0 0
712 5 0 13 8 SG19399 1 0
etc       

We store the whole postcodes separately from the rest of a pupil's answers as below, tagged with two numbers which together can identify an individual case, and merge the information only when necessary, and don't keep the merged data file.

SCHID PUPILID PCODE1 PCODE2
746 2 CB013 LN
746 3 CB013 LN
746 4 CB013 BN
746 5 CB014 ET
746 6 CB013 PU

We have mostly used postcodes for things like allocating pupils to districts - as a pupil may go to school in one district but live in another.  The reports produced are at the level of district rather than at the pupil level.

Elsewhere, we have used postcodes for allocating deprivation scores, assigning ward-level information, and so on; again, we keep the derived information and discard the postcode. An example of an analysis using deprivation scores is given below:

Topics: 

Comments about SHEU

"We're very happy to commission another survey from you. Our colleagues in School Improvement are dead keen to work with us on this. During our last LA Inspection, we were flagged from our Tellus data as having a bullying problem. We could demonstrate with our SHEU data - which had a much better sample size and coverage of the authority - that we did not have the problem they suggested. The Inspectors went away happy and we are definitely surveying again with SHEU."

Local Authority Senior Adviser

"Many thanks for a major contribution to the health of children in the UK and elsewhere over many years and putting in place the continuation of the Unit." Tribute from a Director of Public Health to John Balding, presented at his retirement lunch, May 2005

Director of Public Health

"One year (following the SHEU survey) responses from our Year 4 cohort caused us concern, so we put in place a number of team building, motivational projects. We then assessed their effectiveness by requesting the SHEU questionnaires for these pupils as Year 5's."

Learning Mentor

(Our) Senior team were very enthused with the rich source of data provided within the reports (and thought that the analyses including within the appendices section of the main reports were really interesting).

Health Improvement Specialist (Children, Schools and Families)

"You have made a truly significant contribution to health education and health promotion of young people in, not only England, but all over the United Kingdom and beyond." Colleague from NHS Scotland paying tribute to John Balding, presented at his retirement lunch, May 2005

NHS Scotland

"We use the data to inform whole school practice: Pastoral programmes for target groups of pupils; Items for discussion with School Council; Information to help us achieve the Healthy School gold standard; To develop and dicuss with pupils our Anti-Bullying Policy; Targeted whole class sessions with the Police Community Support Officers; To share pupil perceptions of all aspects of their school life with parents, staff and governers." 

Learning Mentor

"The Schools Health Education Unit is the jewel in the crown of the Health Education Authority." Major General Sir John Acland 1928 - 2006

Major General Sir John Acland

"The system works and I find quite a lot of it useful in my work. I've also recommended it to others."

Teenage Pregnancy Manager

"I have valued greatly the work I have done with the team in Exeter, it has been a highlight of my years here." Health Promotion Specialist

Health Promotion Specialist

"This is amazing! Thank you." (school report)

Headteacher