Is Geoparting worthwhile and when should we use it?
Here's how you can tell--take the state that has the largest number of clicks, and the state with the largest deviation from your overall conversion rate. Check their conversion rates against the overall, just like you would with an A/B test (I recommend the two-proportion test in WolframAlpha). If the certainty is better than 95% for either of them, you should take a look at all of them, and make proportional adjustments where there are significant differences from the overall, and leave the rest alone.
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