Extract a Single Value from a Column with Duplicates, Filtered by Another Column

Hi,

I am wrestling with what I think should be a very simple DAX measure problem, but nothing I have tried yet has worked. Here's the situation:

I have a table with colulmns [Academic Year] and [Current Year Flag]. There are duplicate values in both of these columns, since they are part of a table that inludes all classes offered at an institution, and details about those classes. Because multiple classes are offered in a year, there are duplicate year values.

Anyway, my goal is to calculate a measure (we'll call it Metric Previous Year) based on a particular column's values from a previous year, i.e., current academic year - 1. Someone before me (using an earlier data warehouse source with different architecture and different field names) approached it like this:

Metric Previous Year =

CALCULATE (

    [Metric],

    FILTER (

        ALL ( 'Term Dim' ),

        'Term Dim'[Academic Year Numeric]

            = MAX ( 'Term Dim'[Academic Year Numeric] ) - 1

            && 'Term Dim'[Quarter] IN VALUES ( 'Term Dim'[Quarter] )

    )

)

In other words, they used MAX to find the largest value in [Academic Year Numeric] and subtracted 1 to find the previous year. But in the data warehous source I am working with, there are some [Academic Year] values for years in the future, meaning that MAX will return a higher number than the current year, and if I subtract 1 I will not get last year.

What I need to do is extract a single value for [Academic Year] where [Current Year Flag] = True, then use this year to subtract and find the previous year. As a beginner, it seems like I should be able to do this with FILTER() and DISTINCT(), but something confusing about the context or something else I don't understand has prevented me from getting this working. Any suggestions are greatly appreciated!

Thanks!