That would maybe be a good idea (although there would still be some “garbage” in ranked games too).
Ah, right! I was mostly interested in this question for high-level (or at least “reasonable”) games. I wonder what would be the best way to explore this with just the OGS dataset.
One could calculate game length divided by area for each game and make a histogram like above. I guess this would give a normal-ish distribution but it wouldn’t really verify or falsify the hypothesis. So better would be to plot average length against area - but we have so much more data on 9x9, 13x13 and 19x19 than the other sizes, so different datapoints would have very different confidence. But I think this plot could be interesting, I’ll probably try that at some point.