How does YA determine Top Contributor? What are the standards?

The TC badge is a measure of recent participation on YA. Badges come and go with each new Monday. Yahoo keeps the formula secret (so they can change it if needed). The best guess based on experience of long time users is that you need:

200 or more total points per week

30-50 answers per week in a single category

20 or more BAs in the category within the last 3 weeks (10-15% most people think)

If your level of participation falls below the target levels, you lose your badge. Then you have to earn it back. There are no TC badges for the P&S and Jokes categories.

The first answer has the basic formula for becoming a TC, but it has NEVER been revealed exactly how to become one. YA has always kept that a secret, so there really is no real answer.

In a nutshell, you need about 40/50 answers in a certain category, about 20/30 best answers in that category, and an increase best answer % from those best answers (people say around 10%). All of this needs to happen within 2/3/4 weeks.

You can lose it by simply not getting enough BAs in that category over 2/3/4 weeks. It usually only takes about 15/20 BAs a week to keep the badge. You basically have immunity of the TC badge for 1 or 2 weeks, unless it is replaced with another badge.

Note: you cannot get a badge in Polls & Surveys or Jokes & Riddles.

Top Contributor is not based on overall activity, but on a high level of participation and high Best Answers % IN SPECIFIC CATEGORIES. Most of your answers for the past 2 weeks have been in History and almost all of your Best Answers as well. Therefore you haven't been contributing anything in the 2 other categories where you once were labeled Top Contributor. You need to regain that status again by actually contributing in those categories over the next 2 - 3 weeks.