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For a period of time response to be entered as a duration, it must meet the following criteria: the time period must be for a specific event, for a continuous period of time, and the period must be sufficiently described, so that the start and end of the event are discrete time points. Responses that do not meet these criteria for a duration answer are entered as Numeric answers. See the Duration section of the date and time answers guidance for a detailed discussion of the use of duration versus numeric answers. Examples of time period responses that are entered as a duration answer may be found here. Examples of time period responses that are entered as a numeric answer may be found here.
Time period responses with only one time point (i.e. years only, hours only) are not sufficiently described to be entered as a duration answer and a ‘How many’ answer is entered (Example). When a compound time period response is input as two numeric answers, the first element of the time period is entered as a ‘How many’ answer; the second element is entered as a specifically labelled answer (Example).
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