Originally Posted by bruceames
My research on top 20 behavior shows that any abnormal spikes in marketshare most of the time tends to be due to a sale on the Blu-ray, not the DVD. A recent example would be the clearance sales on poor selling titles like Panda 2 and Rise of the Planet of the Apes. They were priced nearly 1/2 off their original sale price a mere 2 weeks after going on sale, as initial sales were reportedly poor.
Again, the DVD titles have clearly shown to have the legs compared to Blu-ray. And "legs" in this case means behavior after week one and during its reign in the top 20 while sales are still strong. Comparing market share below top 20 is rather pointless anyway, as sales tend to be trivial. Besides, those of us who are not insiders are not privy to top 50 or top 100 data.
Your research considered only titles on the Top 20 Sellers chart which biases the results to titles that have larger DVD volumes so they show up on those charts and to recent releases in the first eight weeks of release. The majority of other titles that do not reach the volumes to hit the Top 20 Sellers chart but we still have BD marketshare info from the BD Title share chart was not considered in your analysis.
But we have the Blu-ray unit marketshare off the BD Title Share chart that gives additional Blu-ray unit marketshares beyond what shows up on the Top 20 Sellers list which by definition has large DVD unit sales as few titles without larger magnitude DVD sales show up on the overall DVD+BD Top 20 sellers chart.
That's a future project for us to look at but you can see that many Blu-ray titles have larger BD unit marketshare over time long after release when you consider that data.