Imputation flags
Imputation flags help you identify derived income values that have been imputed. Imputation is used where a respondent is either missing an individual interview (unit non-response) or does not provide an answer to a particular income question (item non-response). Exact details of the imputation methods used in Understanding Society can be found in Understanding Society and its income data.
For each income variable for which amounts are imputed there is a separate imputation flag variable with a suffix “_if” instead of “_dv” indicating whether the variable is imputed. In most cases the flags take the value 1 if imputed and 0 if not, but in the case of the following variables it shows the proportion of total income imputed: w_fimngrs_if, w_fibenothr_if, and w_fihhmngrs_if.
Top coding of income and investment variables
Because extremely high incomes are rare, releasing this information can increase the risk of disclosure. So, reported and imputed income and investment amounts have been top-coded in order to prevent disclosure of respondents. Individual earnings and self-employment profit as well as investment income and rent have been top-coded at £100,000 per annum or its monthly equivalent less tax and national insurance for net incomes.
Derived total personal income and household income are computed using the top-coded values and there is a set of flag variables indicating whether the computed sum variables include top coded amounts.
The flag variables on the w_indresp data file are:
w_fimngrs_tc, w_fimnlabgrs_tc, w_fimnlabnet_tc, w_fiyrinvinc_tc, w_fibenothr_tc
The flag variables on the w_hhresp data file are:
w_fihhmngrs_tc, w_fihhmnlabgrs_tc
The w_income data file includes the flag w_frmnth_tc.
The following are top-coded at +/- £8,333 per month or its net equivalent:
w_payg_dv, w_payn_dv, w_payu_dv, w_paygu_dv, w_paynu_dv, w_j2pay_dv, w_j2paynet_dv, w_seearnnet_dv, w_seearngrs_dv, w_seearnnet_dv, w_frmnthimp_dv, w_jspayu, w_j2pay, w_paygl, w_payu, w_paynl
The variable w_fiyrinvinc_dv is top coded at £100,000 per annum.
Data from the investment income module in Wave 4 (d_nvestamtrt1, d_nvestamtrt2, d_nvestamtrt3, d_nvestamtrt97) have been top-coded at £1,000,000.
Access to income and investment data without top-coding is available in the Special Licence version of the data SN 6931.
