How to counter Caitlyn
Let us take a look on how to beat Caitlyn. We will look at champions who are strong against Caitlyn and who are weak against Caitlyn. Use win rate, gold difference and creep score difference at minute 10 to find the best 
Adc champion who counters Caitlyn. You can already win in champion select with the right counters for Caitlyn. If you want to know how to counter Caitlyn then you need to take into account the best picks vs Caitlyn and the worst picks vs Caitlyn. This Caitlyn counter data is based on matches played by Pros on patch 14.9 and previous ones. It is important to see whether Pros counter picked Caitlyn or whether they played as Caitlyn.
Champions used by Pros to counter pick Caitlyn
Looking at the matches from Pros (see table Pros counter picked Caitlyn) we can see that they picked 
Jinx most often to counter pick Caitlyn. The matchup Jinx vs Caitlyn occured 32 times. Caitlyn has 19 wins and 13 losses in this matchup. Learn how to counter pick Jinx to get another perspective on the data.
Lane outcome for Caitlyn
When looking at Caitlyn counters you will notice that win rates alone are not conclusional. Therefore we provide an overview (see table Lane Outcome) where you can see the lane outcome of Pros who played Caitlyn. The lane outcome of Caitlyn consists of three outcomes: Win, Loss or Draw. Let's take a look of Caitlyn lane and match outcome for specific matchups. Considering the lane outcome and the match outcome of a specific matchup, might enable you to find the right counter for Caitlyn.
Conclusion
Analyze the available data and learn how to beat Caitlyn. To master Caitlyn take also a look on Caitlyn builds and runes for Caitlyn. Good luck, Summoner!