Hi, 

This error indicates that Pigment can’t compare both dates because they’re not specified by Tenant.

Month.'Start Date' doesn’t tell Pigment which month’s start date to take to compare with.

I made a little reproduction in case it can help you:

It works in my example because each Tenant has two dates attached, a Created date, and an 1st invoice date.

Let me know if you have further questions.

Best,

​@Benoit thanks for your reply.

I wanted to build a matrix, where I have tenants as rows and months as columns. Cells would contain number of months since the tenant registration. Your suggested formula will give one MONTHDIF per tenant, but I also need a dimension of Month in the response.

Or you can recommend another method for building a cohort analysis for MRR? I will aggregate tenants by month cohorts, but in columns I need to have dimension ‘Month delta’, which contains values M 0, M 1, M -5, M 9 showing deltas between the inception month of a tenant and the reported month.

I wanted to use MONTHDIF to get the matrix of tenant/month values of diffs, then convert it to ‘Month delta’ dimension using ‘ITEM’ and then use the result to map MRR report from Month to Month Delta.

Do you have a better idea perhaps?