What causes an LDF of 1.0 and how can this be avoided?

If the incurred and paid amounts for a period are equal, Loss Forecaster automatically assumes the period is fully closed.  Since no further development will occur on a closed period an LDF of 1.000 is applied.  To circumvent this you can increase the incurred amount of a closed period by $1 so that Loss Forecaster will treat it as open.