Perhaps market projections may suffice if you are thinking of investing $200 in a phone and signing a two year contract. A hobbyist or part-time developer, however, may be looking at investing the better part of a year to get up to speed on developing for a new platform (not to mention having to buy the hardware). More important is the opportunity cost of spending less time and becoming less competitive in the platform where all of the current users are.

I see clinicians walking around with iPhones multiple times per day. I have yet to lay eyes on a Droid. As long as I can reach 20 or more iPhone OS users for every Droid user, free app or not, it’s a no-brainer. This positive feedback loop of developers following users following the software that developers create is exactly why Palm OS PDAs took off among clinicians and didn’t let up until Palm dropped the ball with smartphones.

You mentioned some great points in your comments. Do you think if the popularity of the Droid continues at its current pace, and if studies show it comes close to rivaling the iPhone, would you consider developing for the platform?

Much of this is niche software that is developed and launched by one person, often a hobbyist developer who is a full-time clinician. It’s simply not realistic to think that a part-time developer is going to develop software for a device that they do not currently own or use. As long as you see ten to twenty times more clinicians using iPhones or iPod Touches than any other platform, you will see that same distribution in the clinical software selection.

Mainstream developers may move away from iPhone OS development to avoid intense competition in the App Store for general apps, however, clinical app developers don’t usually have that concern. If I’m developing an app to do something that doesn’t currently exist on a mobile device then I’m going to look at whatever is the dominant platform.