Research and analysis

Trade Union Membership Statistics: Sampling Variance

Information about the quality of the trade union membership statistics, in particular sampling variances and confidence intervals.


Sampling Variance in the Trade Union Membership Statistics


The Department for Business, Innovation & Skills (BIS) trade union membership statistics are mainly based on the Labour Force survey (LFS) which is based on a sample of households. As the LFS is a sample survey, the estimates are subject to a margin of error.

This document provides information about confidence intervals for the trade union membership estimates. It covers sampling variance, and how confidence intervals are used to estimate the range of accepted variance around the sample means.

Published 8 April 2013