99.999% of the time, Meditech NPR uses indexes to provide efficient access to data just as you'd expect. 

I am aware of 1 situation where the MEDITECH NPR Report Writer will use an index by default, even when you haven't specified an index. When this index doesn't contain all information from this mission critical data structure it represents, you won't be able to report on everything in that data segment.

In the following white paper, you'll see first hand what this looks like when it happens; how to validate other reports, and how to prevent it.