I'm very lazy. I would never be able to compare hundreds of item types every day or maintain hundreds of buy and/or sell orders. But there's a lot of money in trade, so I keep thinking about it, trying to find an easy way to do it.
It would be easy to write a program that uses eve-central data to compare item prices in different market hubs. However, if you only look at prices, all the program's top results
would be very expensive items, like capital ships and deadspace modules. Eve-central doesn't track how many units are sold per day, so it's impossible to calculate profit potential.
And then I thought, "or is it"? Eve-central does track how many units of an item are on the market, and I'll bet there's a correlation between how many units are on the market and how many units are sold per day.
Of course, the market being what it is, there will never be a particularly strong correlation -- but it doesn't have to be strong. It just has to tell me that moving a bunch of nocxium at a profit of 10 isk per unit is more profitable than moving a single unit of whatever at a profit of one million per unit.
So I took a sample of item types and blah blah spreadsheets and quadratic regression blah and got this:
The sample size is way too small, but I can always go back and redo the equation with better numbers. The point is that it more or less works and I can tell how many units are being sold to within about an order of magnitude.
Next step? Sorcery.