According to CNN both EA and Activision are offering some not-kind words about the NPD sales data that gets released. In particular, NPD sales data for February doesn't seem particularly spectacular, though both publishers have data as to how their own companies are faring with sales performed online. As Ken Sweet, the writer, goes on to point out, the contention rests primarily in the fact that NPD offers consistent data only on retail sales (they do publish a quarterly report that does look at the digital distribution side), so as a measurement of the industry on a month-by-month basis, it is not a wholly accurate view.
The question rests in where one gets this data. Particularly when you consider the strength of sales that might occur in both iTunes and Facebook games--something NPD does not report on at all. Of course, as the article also points out, this is in many ways shooting the messenger. Valve, for instance, does not release its data of sale numbers, and while companies have those numbers, they do not reliably release them either. This means that there is no way to easily access that data unless you talk to each and every one of these publishers.
Therefore, if one looks at this, the fault is not solely NPD's, but rather indicative of a larger problem in the games industry. While I have seen smaller indie companies post information about their sales data every few months--particularly in analyses of how certain price points or word of mouth marketing works--I rarely see larger companies doing so. Therefore, I get a sense that if we want to see the NPD lose some significance as the health bar of the industry, we need more channels that provide information. In the case of some place like Steam, that responsibility, for now, seems to reside in the publishers' hands themselves.
Therefore, instead of just lambasting NPD for inaccurate numbers, I would like to see them step up and push the industry in a direction that allows for more transparency. Digital distribution is not going to be the only way to sell games any time soon, and while I have moved that direction with my PC gaming, I haven't even considered it on consoles (largely, the market doesn't exist to support it yet). Those retail numbers are important, and finding the way to provide both will take work that I'm not sure we can responsibly foist on the NPD itself.