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Analysis report for common sense in media ~ A-time share%2014.03.01

SPI reported on the analysis for “common sense in media”, to reconsider the “significant point”.

This time we focused on “A-time share%” , which is normally regarded as important when buying TV media.

*Definition of “A-time share%”
A-time is called “Prime-time” in general, which is around 7~11pm, the highest TV-rating zone of the day.
A-time share% is calculated by A-time GRP / Total GRP.
**Note; TVCM on air day & time is difficult to control in the case of TVSpot (NOT Sponsored programs) in Japan (Not like in the US or western Europe).


*Why is there a time rank?
There was no reliable TV-rating when TVCM when buying started, therefore, TVCM purchasing was based on the number of CM (=Spot) bases, however, its prices are ranked by timezone (to reflect its value).

*Contradiction in buying the TVSpot based on GRP
Almost of the advertisers buy TVSpot by GRP base referring to TV-rating (higher TV-rating zone becomes higher buying-costs), therefore, time rank seems to have lost its significance.
Therefore, SPI analyzes the significance of A-time share% in TVSpot buying.

1, Conversion ratio of Individual-rating
GRP should be based on the “Household-rating” in Japan when buying a TVSpot.
The “Household” rating in A-time has a much more “Individual-rating”, therefore GRP in A-time is much more important than GRP in other zones. 201403_2.png

2, reach expansion
GRP is the Gross Rating Point, therefore, you can say that 2GRP means “the same person might have watched twice”.
Therefore, getting higher GRP with a CM is better in expanding reach compared with less GRP.
For example (as a possibility);
*2 GRP by 1 CM = 2 people watch once >>>reaches 2 people
**2 GRP by 2 CM = 1 people watch 2 times >>>reaches 1 person

3, impact
SPI found the possibility that a TVCM in A-time has more impact than in other zones, because the quality of TV-watching then might be better than during other times.
There is the comparison of TV-ratings between “machine-based = VR (TV-rating is counted by channel on/off)” and “questionnaire based = SPI (TV-rating is counted by samples’ answers)”.

This analysis illustrates “machine-based = VR (TV-rating is counted by channel on/off)” is lower than the “questionnaire based = SPI (TV-rating is counted by sample’s answer)”. We see there is a possibility that A-time TV programs have better condition audience viewing conditions.

From these reasons, SPI understands that A-time share% is important in improving TVSpot performance.


Shiro Kokue
Senior consultant


…This report and its contents are NOT officially guaranteed by SPI, though SPI may deem it worthy according to reliable information, resources & methodology.
…This information is confidential and belongs to the copyright of SPI. Any references to this information are to be noted as, or contain the phrase ‘according to SPI’ .