It is often accused by detractors that God doesn’t really answer prayer, but that Christians are guilty of confirmation bias. It’s the tendency to see what we want to see and expect to see, to say that certain circumstances are answers to prayer because I believe they are. When I expect to get an answer to prayer, I will find some event that fits my expectations, and then claim that it happened.

I claim this accusation is not only untrue but also impossible.

1. To know it was confirmation we would have to be able to isolate the events on earth that were acts of God and those that weren't, so we could know what was a false assumption and bias. That's not possible.
2. We would have to be able to guarantee who was praying for the object and hand and who was not, and how they were praying. Any stray prayers may skew the data. Such a guarantee is impossible.
3. We would have to establish objective criteria for what counted as an answer to prayer and what did not. Knowing that God at times uses very natural and normal means, that sometimes he answers the prayers in a different way or by a different means, sometimes he answers partially and sometimes in stages makes such criteria impossible.
4. We would have to construct a model or standard by which we can discern what answers to prayer are legitimate and which are contrived. This is impossible.
5. We would have to have an ironclad control group that eliminates all possible other factors. This is impossible.
6. We would have to know with certainty what circumstantial events are answers to prayer and which are not, which is impossible.

Therefore any accusation of confirmation bias is illegitimately. Prayer can not be measured in that way.