# Comparing strategies of varying cycle length

Hello all! I am trying to do a cost effectiveness analysis of a screening test using markov modeling . I am comparing the same test but at different duration. That is, one strategy will have the test repeated every 2 years and another strategy will have the test repeated at 5 years and another at every 10 years. How do I create a markov model and account for different cycle length between strategies?

## Comments

Andrew MunzerI strongly recommend that you use the same cycle length for each strategy.

You can, however, implement different screening intervals with logic to screen in some cycles and not in others.

Something similar to this for the probability of screening...

The logical expressions above will return be true and return a probability of 1 only every 5 or 10 years.

Note that these screening decisions can be more complicated based on when screening regimens begin/end, but the modulo function should help.

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