Scottish Health and Care Experience Survey 2013/14 - Technical Report

Annex E Significance Testing

a. Comparison of results at National, NHS Board and CHP over the two survey periods (2011/12 and 2013/14)

For each question (where comparison is possible), the test statistic can be calculated as follows:

For a result in 2013/14 to be not statistically significantly different from 2011/12, then

To illustrate this, let the:

• percentage positive score in 20011/12 and 2013/14 for Scotland, an NHS Board or CHP be denoted by p₁ and p₂ respectively.

• number of valid responses in 2011/12 and 2013/14 be denoted by n₁ and n₂ respectively.

• design effect in years 2011/12 and 2013/14 be denoted as deff₁ and deff₂ respectively.

Then the standard error can be calculated as:

b. Comparison of results for NHS Board and CHP with Scotland

For each question (where comparison is applicable), the test statistic can be calculated as follows:

For the NHS Board or CHP to be not statistically significantly different from Scotland results, then

To illustrate this, let the:

• percentage positive score for NHS Board or CHP be denoted by p_geog.
• percentage positive score for Scotland be denoted by p_Scotland.
• number of valid responses for NHS Board or CHP (geography) be denoted by n_geog.
• number of valid responses for Scotland be denoted by n_Scotland.
• design effect for NHS Board or CHP and Scotland be denoted by deff_geog and deff_Scotland respectively.

Then the standard error can be calculated as