Determinants are one of the most confusing aspects of Framework Manager and are therefore the least understood. As a result, many modelers will never use or create them. However, determinants can play an important role in the performance of your Framework Manager model.
Determinants allow a table with one level of detail (or granularity) to behave as if it has a completely different level of detail. Generally determinants will be used with dimension tables, where fact tables join the dimension table at more than one level in the dimension.
A common example of where determinants would be used is with a date dimension table, with a granularity at the day level. If all the fact tables are joined to this table at the day level, there would be no need for determinants.
A join between a monthly forecast table aggregated at the month level with one row per month, and with this date dimension table would return between 28 and 31 records, depending upon the month. This could cause problems...