Measure liquidity on Bitcoin exchanges

[Grap]

Hello!

In my thesis about Bitcoin I am going to examine different Bitcoin exchanges where I among other things want to measure the liquidity.
I wonder if you have any tips on what kind of method I should use? I want to make the calculations in MS Excel and collect the data from bitcoincharts.com.

Best regards.

[knightcoin]

nice question ... I wondering how they do counterparty risk, portfolio stress, etc ..