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NRS April-September’92: Bulletin 11

NRS have issued a bulletin (11) which seeks to clarify the rules and recommendations concerning use of the NRS data produced by the CAPI (Computer Aided Personal Interviews) methodology.
1) Comparisons of titles based on latest available data:
* Use CAPI data on its own if possible. (eg. All Adults Jul-Sep’92 for titles publishable on a 3 months database). For breakdowns involving smaller sample sizes than All Adults it is recommended to use the six months combined CAPI/pen and paper April-September 1992.
* Use combined CAPI and pen and paper data (eg. 6 months Apr-Sep 1992 or 12 months Oct 1991 – Sept. 1992) when comparing a set of titles which include any that are publishable on 6 or 12 months only.The base must be determined by the smallest title, according to its publishable base, either 6 months or 12 months as applicable.
2) Comparison with pre-CAPI data:
* Comparisons of data involving CAPI with pre – CAPI pen and paper only periods are not recommended, due to change in technique. Readership levels produced by CAPI (or by a combined CAPI and pen and paper base period) cannot directly be compared with those of the previous technique. NRS stress that if for any reason such comparisons are made, a footnote must point out that any observed variation in readership levels may be due to the change in technique, and not attributable to market-place changes.
NRS: Roger Beeson: 071 379 0344
AVERAGE ISSUE READERSHIP INDEX ON 1991
Pen&Paper CAPI CAPI Jn-Jn’92 Pilot’91 Jl-Sp’92
Dailies 94 96* 105 Sundays 96 98 100 Gen Wkls 92 100 98 Wmns Wkls 91 113 106 Gen Mnthls 96 106 107 Wms Mnthls 98 115 117
ALL 95 104 104