I think data tracker app isn't worth the money. Personally, I prefer the Percentally app instead. It's only $2.99 and lets you do so much more I feel. You can do just single tallys, to track behaviors or something, or you can do the traditional correct/incorrect 2 button tally. I would love if they could add 3 tallys for one objective (like correct, approximate, incorrect). But it's an awesome app! You can also email the data or send it to a google spreadsheet. Super convenient.