Excel: Count distinct numerical values if string condition matches

Question

I have a list of employee names on one tab and another tab with orders shipped by employees and the month they were shipped going back 12 months. I'd like to calculate the average number of products shipped per employee per month, but I need to know how many months they were here to do that. So what I'd like to do is essentially write a formula that says give me the count of the distinct number of months they've been shipping products.

Sample employee data:

And here's the sample data on the individual shipments:

So in short, I need to know that Joe Smith shipped those 250 products across 3 distinct months to see he averages 83.3 shipments per month. Again, because there are many new people who have come onboard in the last 12 months, I can't just divide them all by 12 and need to know how many months they were shipping items in.

Answer 1

FILTER Shipper and Month based on Shipper column with criteria Employee name. Apply UNIQUE on filtered array to get only unique values (name + month number). Use COUNT to get active months. Divide Products Shipped by it.

Result: