The problem with the tablet-notebook debate

August 10, 2011, 2:50 PM UTC

By Dan Mitchell, contributor

FORTUNE — Much is being made of a research note from Deutsche Bank analyst Chris Whitmore that says Apple is the leading seller of notebook computers – if you consider the iPad to be a notebook computer that is.

Following the natural human propensity to take a hard position on one “side” or the other, people are debating whether tablet computers are or not notebooks. The truth is, in some ways they are and, in other ways, they aren’t. If tablets aren’t notebooks, then Apple (AAPL) falls from the top position to dead last among the top six notebook makers.

Some tablet sales are to people who would otherwise have purchased a notebook. Other sales are to people who already have a notebook, but want a tablet for supplementary tasks. Other sales still are to people who have no notebook and have no need or desire to own one. I know a 12-year-old girl whose ownership of an iPad didn’t affect notebook sales one bit. I know an adult man who bought an iPad to replace his notebook and doesn’t plan to buy another notebook any time soon. He took share away from the notebook market and added share to the tablet market. I know lots of people who own both a tablet and a notebook.

Unless the market is examined at this level of granularity, the only sure thing is that tablets are taking some amount of market share away from notebooks. How much of that share isn’t known for sure. (I looked, but couldn’t easily find, any data on this – if you know of any research analyzing sales trends at this level, let us know in the comments.)

Some of the notebook market share being eaten is Apple’s own.  But I don’t think too many people in Cupertino are complaining about that.

The other complicating factor is that, the more functional and notebook-like tablets become, the faster the argument becomes moot.

In the meantime, there’s really no need for a debate. The data can, and should, be crunched in all kinds of ways. You can run the numbers assuming it’s all one big market, and then run them again assuming it’s two separate ones. That’s pretty much what Whitmore did here. Or you can make assumptions about how much of the notebook market is being cannibalized by tablets, and run the numbers based on that.