How long does it take Amazon Attribution data to mature?

Here's a look at how the data pulls have looked for a launch that I'm running. (It took me a few days to get the data set up so that's why Day 1 was already 5 days old when it was initially pulled.) After about a week, I went back and re-pulled those same days to see how the attribution data had matured. This is what I found.

This isn't the smoothest analysis that someone could perform, but it looks like the most extreme changes in attribution data happen between Day 1 and Day 3.

Between Day 1 and Day 10 it looks like the data changes between 20-30%

Between Day 2 and Day 12-14 that change is only 10-13%.

There is an outlier in here with a huge change in data (68.1%) between days 1 and 10. That is because the spend dipped to $310 the previous day and shot back up to $3740 so the massive shift in spend volume is likely responsible for the huge change in attribution reporting.

But in general, at a spend of over $1k/day, it looks like Data is probably usable after 5-7 days, or 2-3 days if you need to make faster less-informed decisions (although my hypothesis is that semi-accurate readings after 2-3 days are more a product of steady high spend).

Anecdotally, I have noticed at lower spend ($100/day) it will sometimes take 4 days for KENP reads to begin showing up with about a week of lag before the data is accurate enough to make judgment calls with. But this is something I also need to test to confirm.

It's still early going with this particular test so I'll report back when I have a larger sample size but hopefully this helps give you an idea of when you can begin to trust your attribution data.