You would only be able to do this by defining the criteria for the report and taking a snapshot of the information for analysis going forward.  You couldn’t retroactively create a report for this information.  The request is a moving target that changes day by day and would require limits around what is determined as a back order.  Did the order get reserved on that day?  Did it get Delivered?  Is the date late based on the Wanted Delivery Date on the day it was delivered?  What if an order is rescheduled?  There are a dozen parameters I can think of quickly that would need nailed down, then you would almost have to do a daily review and aggregation of the resulting order line data to determine a backorder per period.  Even then, it would only be at the sales part level.  Assuming that you don’t have a shortage of only the top level catalog item only, rather there are child items at lower levels also driving the backlog, you would need to be able to relate the sales part on the customer order line with the due date to the inventory part or parts that led to the actual shortage at the moment the order was Reserved or Delivered - again, whichever criteria you’ve chosen as the measure.

The more I imagine the report, the more complex it would become I think - even without knowing your products.