Hi, I've been looking into different sites presenting market cap lists for cryptocurrencies and have seen that there is a lot of variance.
 - Not the same market cap value for a currency in the lists.
 - The top 5 are different on each list.
 - Lists range from showing 300 to 3000 different coins

Question is if there is any consensus about which one is more trustworthy than the other?

I'm writing a master thesis in the subject of technology trajectories affecting the variance in cryptocurrencies and need to have reliable data.

Take a look at these which I've been looking at:
http://www.cryptocoinrank.com
http://www.cryptocoincharts.info/coins/info
http://coinmarketcap.com

Any comments are valuable.
Thanks
B. S. Adams