I am teaching TBL first time this term and one of my bright students 
suggested that I should use the same system for iRat and tRat to make the 
tests more fair. Currently I am using IF ATs for the tRat and for the iRat 
a 'hedging' system where students can allocate either 4, 3, 2 or 1 point(s) to 
the four alternative answers (e.g. 4 if they are certain they know the answer, 
3 if they are fairly sure with 1 point on an alternative answer...). My bright 
student suggested to use an iRat based on preferences - such as answer a) is 
my first preference then c) then..... He (bright student) suggested this would 
more closely resemble the tRat. I am not sure that this would improve the 
system in any way. I would be interested in what iRat methods other people 
use and any thoughts on my student's suggestion.