# Formula to discard items by votes (Lower bound of Wilson score confidence interval)

I'm developing an application in which users can create 'sections' (à la subreddit in reddit), in which items/posts can be created and voted with a thumbs-up/down system.

A great article guided me on how to sort these votes so that an item with a 100% positive response but with few votes won't get ranked over one with hundreds of votes and an acceptance of 80%. The article describes it pretty well.

However, I'd like to discard the lowest-ranked items and this is where it gets tricky:

• How could I know the minimum number of votes in order to discard it?
• What is the score's threshold required to discard the item?

As I said, there are sections, and each one has items (which are the ones voted). The formula has to take into consideration the fact that one section may have 100 items with thousands of votes and another might have 3 or 4 items with 20 votes, so a minimum of 40 votes required might be optimal for the first case but totally out of bounds for the second.

(I was tempted in posting this to MathOverflow, but I'm not really sure since this also involves some programming)

Thanks!

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## merged by whuber♦May 17 '11 at 16:16

this question was merged with Formula to discard items by votes (Lower bound of Wilson score confidence interval) because it is an exact duplicate of that question.