Support #1309

Difference between variable nfh20 and bentax5

Added by Alexander Tromp about 3 years ago. Updated almost 2 years ago.

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I am studying Working Tax Credit. I am wondering what the difference is between the variables nfh20 and bentax5. Of the 221 people who report receiving additional income from Working Tax Credit, none of them report receiving WTC in variable bentax5, they are mutually exclusive. Could you tell me the difference between the two? Many thanks for your help.


Updated by Stephanie Auty almost 3 years ago

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Dear Alexander,

You can find the answer by reading the full pdf questionnaire, which you can download here:

According to the online documentation, Wave 5 is the last time these two variables both appeared. bentax5 appears first and asks if the respondent receives tax credits of each type. nfh20 appears later and uses fed-forward information (as calculated in missource) to check whether any benefits reported in the previous wave but not this wave are still being received, as a reminder to help with consistency of what is reported.

Best wishes,


Updated by Alexander Tromp almost 3 years ago

Thank you for your quick and helpful response.

The questions in the pdf are very similar as you can see below.

This is the NFH question:
Can I just check, according to our records, you have in the past received [ff_bentype01 - ff_bentype41]. Are you currently receiving[ff_bentype01 - ff_bentype41]either just yourself or jointly{if HHSize > 1 & (livesp = 1 or livewith = 1)}?

This question is the same from Wave 2 up to and including Wave 9.

This is the OTHBEN question:
Are you currently receiving any of these payments ,either just yourself or jointly{if hhsize > 1 & (livesp = 1 or livewith = 1)}?

This question is the same from Wave 6 up to and including Wave 9. Between Wave 2 and Wave 5 the same question is being asked, but then in the variable BENTAX.

From the questions one would expect that there would be a considerable amount of people mentioning receiving WTC income in the NFH variable and at the same time mentioning that they are receiving it in OTHBEN (or the older BENTAX variable until Wave 5). But the opposite is true, there is no overlap, they are mutually exclusive. Because this seems so unlikely to me, I wanted to explore the difference in definition between OTHBEN and NFH further.

Could you explain why the observations are mutually exclusive, i.e. there is no one mentioning receiving Working Tax Credit in NFH who mentions receiving it in OTHBEN and vice versa? Maybe there is some obvious explanation I am missing here. Again, many thanks.

These are links to the variables concerning Working Tax Credit:


Updated by Stephanie Auty almost 3 years ago

Dear Alexander,

At the end of the section for the question nfl, the pdf version of the questionnaire says:

In loops
Loop for each MisSource = 1

Therefore this question is only asked for those benefits flagged in Missource: Income source enumerated at previous wave but not current wave

Scripting Notes for Missource:
MisSource is an indicator designed to identify benefit and unearned income sources that were not recorded at the current wave but were recorded at the previous wave. A flag is created for each unearned income source if it has been coded as received in the current interview. This flag is then compared with the ff variable for that income source. If enumerated at wave t-1 and enumerated at wave t then MisSource = 0. If not enumerated at wave t-1 and not enumerated at wave t then MisSource = 0. If not enumerated at wave t-1 but enumerated at wave t then MisSource = 0. If enumerated at wave t-1 but not at wave t then MisSource = 1.

So if an income source is already enumerated at the current wave, it will not be asked about again in nfl.

Best wishes,


Updated by Understanding Society User Support Team almost 2 years ago

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