I think you're missing my point. I wasn't trying to say that the ROI would be better on Facebook with a bigger budget (though, I guess anything is greater than

I think you're missing my point. I wasn't trying to say that the ROI would be better on Facebook with a bigger budget (though, I guess anything is greater than 0%). I'm saying that your budget is too small to make the numbers you're seeing anything else than statistically insignificant luck. Imagine taking a coin toss and trying to figure out whether heads or tails came up more often, but only tossing the coin three times. Imagine you get HHT, and conclude that head is a better bet than tails. This is essentially what you're doing, by concluding that one option is better than the other, based on a single-digit install sample size. Now, I'm not saying you should be spending massive ad budgets, and spending a lot of time tweaking your campaigns, I'm merely pointing out that you don't have enough raw data to make conclusive judgements about the effectiveness of these two networks. Being a major player in this industry, I can tell you that the numbers I'm seeing seem to indicate that Facebook (and Chartboost) are in fact much more effective ways to buy installs for mobile games than AdMob, with a properly set up campaign. Feel free to contact me directly if you'd like more insight regarding this.