Many states choose to use a separate time study for each cost pool. The state then can apply all the resulting percentages from each time study to that one cost pool when claiming. However, it is also permitted to include multiple cost pools in one time study. If a state elects to include multiple cost pools in one time study, each allocation percentage must only be applied to the applicable cost pool. (See page 125 of the Comprehensive Guide.)
If a state elects to include multiple cost pools within one time study, the moments must be apportioned between the cost pools based on the number of individuals in each cost pool or some other methodology (e.g., using the total costs of each cost pool); provided that all the moments in the time study add up to at least the minimum required sample size (i.e., number of moments) for statistical accuracy and validity. The procedure for determining the number of moments sampled from each cost pool should be described in the Time Study Implementation Plan submitted to CMS.
For example, suppose 443 moments are spread across all staff with an equal probability of being distributed to perform each activity. In that case, the resulting allocation percentages from the time study must be applied to the costs for the entire universe of participants in the time study. All applicable staff would be treated as one cost pool.
On the other hand, a state could divide the universe of staff participating in the time study into different cost pools and still conduct one time study for all staff. In that case, each group of individuals performing similar activities (i.e., each cost pool) should be assigned an applicable fraction of the 443 moments in the time study. The resulting time study allocation percentages would be applied to each cost pool individually.