How much unplanned work is there? This graph distinguishes the total work from the remaining work and charts it into planned and unplanned. Very few projects identify all of the work to be done ahead of time, even within the iteration. This may be perfectly acceptable, if you schedule a sufficient buffer for handling the load of unplanned work (for example, bugs). On the other hand, it may be a real problem if you have not scheduled the capacity and are forced to cut back on the planned work.