I'm working on a computer program but I need help coming up with a formula. This program has list of customers that wrote reviews for products. For each review written by this customers there is a number of votes and also a number indicating how many of these votes marked the review as helpful (think of Amazon).
And I would like to come up with a shorter list of expert reviewers. The way I envisioned my solution was to assign weights to each customers based on the votes given to the reviews, so I thought a ratio between the number of votes and number of those votes marked as "helpful" could be meaningful.
However, I ran into instances in which one reviewer had 1 vote and that one vote was marked as helpful, thus the ratio = 1/1 =1
And there are some other instances in which a customer had 19 votes and all of those votes were marked as helpful. that is 19/19 = 1
It's evident that mathematically they are similar; however I would like to assign a bigger weight to the customer who got 19 votes versus only 1. Similarly, I believe a review that got 24 helpful votes out of 25 (24/25 = .96) should have a bigger weight than the customer who got 1 vote which was marked as helpful.
Do you have any thoughts on how I could come up with a formula that takes into consideration the ratio and also the number of reviews?