Mann-Whitney Test: does the direction of causation matter?

[Luke Lindsay <luke.lindsay@gmail.com>]

I have an ordinal measure of risk aversion and binary variable 
indicating whether a subject opted to play a gamble.

I want to test whether there is a relation between these two variables. 
 One way would be to run a probit/logit e.g.

probit accepts_gamble risk_aversion

However, this is obviously unsound since the measure of risk aversion is 
ordinal.

Would it be appropriate to run a Mann-Whitney Test ‘in reverse’ e.g.

ranksum risk_aversion, by(accepts_gamble )

If not, are there any other tests that would be appropriate?

Any pointers greatly appreciated.

Luke
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