2. Income Non-Response in the Millennium Cohort Study
(MCS)
2.1 Sweeps 1 and 2 separately
The MCS sample is made up of two groups of respondents: the original sample of
18552 families and an additional 692 families who were missed in the first sweep.
For each family a main respondent was identified, who was usually the mother of the
cohort child, and if possible a partner respondent was identified, who was usually the
father of the cohort child. In both cases we shall consider only those who report
being currently employed (either in post at present or on leave including maternity
leave) and include both the employed and self-employed. For a small proportion of
partners a proxy interview was completed by the main respondent. The proxy
response to income is considered separately from the partner response. In both
sweeps of the MCS the main respondent and their partner individually report their
income. They were asked to report both their net and gross income if they were
employed and their take home income if they were self employed.1 For this analysis
of income non-response we shall count someone as responding to the income
question if they provide a response to their gross and/or net income if they are
employed, and provide their net pay if self-employed.
For the 18552 original respondents in the first sweep, the distribution of the main
respondent income response is given in Table 1(a). Of those who did not respond
1.8% were „don’t knows’ and 0.9% refused to respond. Nearly all of those who are
not eligible were not employed at present (51.4%).
Correspondingly for the partner respondent (Table 1(a)): those who did not respond
can be divided into „don’t knows’ (2.1%) and refusers (2.1%). Those who were
ineligible can be divided into those who were not employed at present (8.2%), those
who completed the proxy questionnaire (1.0%), those where no partner lives in the
household, that is lone parents, (13.9%) and other not applicable (8.0%).
At sweep two 14898 of the 18552 original respondents were interviewed and 4.4%
either refused or did not know their income, a higher proportion than for MCS1 (see
Table 1(a)). Moreover, for the partner respondents, 8.7% refused or did not know
their income compared with 4.3% in MCS1. Excluding the „not applicable’ group, we
find that item non-response for income goes up from 5.6% to 8.0% for the main
respondents and from 6.2% to 12% for the partners.
1 Those employed are asked the following two questions:
1. Last time you were paid (in your main job) what was your total take home pay - that is after
all deductions for tax, National Insurance, union dues, pension and so on, but including
overtime, bonuses, commission and tips? Range 1..999997 [refuse, don’t know, missing]
2. And the last time you were paid what was your gross pay - that is before any deductions?
Range 1..999997 [refuse, don’t know, missing]
Those who were self employed were asked:
1. I know that it is sometimes difficult for self employed people to give an exact figure for their
income, but could you please think about your take home income in the last 12 months. That
is, the amount you personally took out of the business after all taxes and costs. About how
much is this? Range 1..999997 [refuse, don’t know, missing]