Here are those examples with the actual magnitudes of the TheNumbers Bluray estimates multiplied by the variation to give an order of magnitude of the possible variations. In most cases the difference is the error of applying the non Walmart considered Nielsen Videoscan first alert percentages against the percentages of Thenumbers in that slow volume period of the year where TheNumbers is including Walmart DVD sales (and a lower rate of Bluray sales) while Nielsen Videoscan is not.
But it should be less of a factor now as Walmart is now closer to the rest of the market in Bluray marketshares as Bluray has matured and become more mass market and mainstream.
Code:
Date HMMshare Numbers Title
12Jun 52.6% 47.0% True Grit (736,835 x 5.6% = 41,262)
19Jun 57.2% 48.1% True Grit (375,018 * 9.1% = 34,126)
26Jun 43.4% 29.0% The Adjustment Bureau (122,305 * 14.4% = 17,611)
3Jul 61.4% 49.1% Sucker Punch (265,856 * 12.3% = 32,700)
10Jul 49.8% 39.8% Sucker Punch (69,464 * 9% = 6,251)
17Jul 42.5% 36.6% Rango (352,502 * 5.9% = 20,767)
24Jul 42.5% 33.8% Rango (317,392 * 8.7% = 27,613)
31Jul 41.1% 32.9% Source Code (188,845 * 8.2% = 15,485)
Quote:
Originally Posted by bruceames
Here are the top titles, and the Bluray share HMM vs. TheNumbers, for several consecutive weeks last summer
Notice that the Bluray share for TheNumbers is quite a bit lower. I didn't calculate for the May and early June ratios, but they are probably similar, with TheNumbers giving lower Bluray shares. Lower Bluray shares would mean lower units for Bluray. That's why you can't just scale the DVD data and assume HMM Bluray shares. Hope this helps.

Well its been a lot closer since Aug 2012 between the HMM and TheNumbers marketshares so using the DVD estimates against the NV unit percentages will give about same result as their Bluray estimates going forward. but the only advantage is you can self calculate them out a day or so earlier than when the Bluray Top 10 chart is released when you get the TN DVD Top 30 chart and combine it with the NV BD percentages. Otherwise the ratios are the same results down the line for the index numbers. The leading #1 title or the DVD estimates really just scale the magnitude of the unit estimates, the unit percentages and the relationship of the Index numbers of the Nielsen Videoscan lists and the TheNumbers lists are about the same now for most weeks for most titles. The only thing the TheNumbers does is scale the magnitude. But in comparing the TheNumbers estimates to one another they generally should exhibit the same bias or house effect. The only time since August 2011 when that has not been the case was when they mentioned it on a couple occasions (Thor was one time the first week TN was off)
By all reports since last fall the Walmart BD share of the market since the 4Q 2011 period is now close to their 40% traditional DVD share so for most genres the reported Nielsen Videoscan first alert numbers will be closer now to the truer Bluray share for the entire market.
In the summer period you also are looking that above that's also a lower volume time so the percentage variation will equate into a smaller absolute unit magnitude variation as well. Then of course they are just estimates as well for any title each week and expected to be 5% to 10% accurate so that sort of variation would not be surprising. If anything the current close match between the TheNumbers and Nielsen Videoscan Bluray unit marketshares since August 2011 is almost too close.
If the question was the 4Q 2011 and 1Q 2011 and 2Q 2011 or earlier calculations using that method its clear that the TheNumbers ratios that were supposed to include Walmart in the consideration should be lower than the Nielsen Videoscan percentages that did not include Walmart in the Nielsen Videoscan first alert point of sale census. That's exactly what you should expect, the figures that include Walmart should have a lower Bluray unit revenue share than the figures that did not consider Walmart.
Units are less of an issue for TheNumbers than revenues , especially for first week of some major releases where it seems they still do not have a good handle of estimating Walmart Bluray revenues for some genres. Their DVD estimates at least seem to be consistent in methodology since 2006 as well and follow the same trends as other sources throughout the year.