Getting error-like response when using RankPrev for Buy rule in Sim

Research
1

I am trying to use a Buy rule in a sim that says:
RankPrev(0) > RankPrev(1)

The Sim does not complete and I get this response:
Required date for RankPrev is not available

I have tried different weeksago combinations and it does not seem to make a difference. RankPrev shows up in Help for Sims so I assume it is an allowed rule.

Any ideas why I am getting this response?

2

Hi David,

Delay the start date of the simulation by one week.

Walter

3

Right. Thanks. I started the sim on 01/15/1999 instead of 1/2/1999 and it works now. I appreciate the help.