17 May 2011
The 2011 wave of data collection is finished and we have 2,057 respondents. We have gone through several waves of data cleaning. For example, we were able to recover many missing occupational codes. In some cases, we found that the interviewer had written down an abbreviation for the occupation. When the person coding the occupation did not know the abbreviation, it was coded as missing data. With some work we found what the abbreviations meant and we were able to code occupation for 21 additional cases.
Occupation is a critical variable because it is the basis for so many other key variables. Socio-economic status, occupational prestige, and class status are all based on occupation, so minimizing the number of missing cases is very important. We are satisfied that we now have a clean dataset. It is a great feeling to work with a new dataset and be able to get on with the work for the 2011 Report.
The data collection effort required about 5 weeks and contacted 4,160 people. 1,324 refused to participate for various reasons, ranging from being not interested, ill, or unable to speak English. The resulting response rate was 51.4%. This is considerably lower than the 2009 response rate of 61.8%. The contractor who collected the data, ICM, reports that response rates have been falling for face-to-face surveys, and they say that this response is higher than the typical response rate that similar surveys have achieved recently.
When we looked at the gender, age, and social economic grade breakdowns, they are usually within 1% of the same category in 2009. In only two cases is it larger: the 35-44 year-old group is 16% in 2011, compared to 19% in 2009. It is 18% in the population as a whole. The over-65 age-group is 28% in 2011, compared to 26% in 2009. It is 19% in the population. The relatively close match to the 2009 results suggests that the deviations are ordinary garden-variety sampling error. This suggests that the lower response rate did not damage the representativeness of the survey.
We are constructing variables, creating graphs, and preparing analyses for the 2011 Report, which will be released in October.