I'm trying to track a metric regarding meeting our artifact delivery
committments and need assistance in calculating the percentage between
two dates.

For example, if the Target column date was 03/31/11 and the Complete
column date 03/31/11, then the Metric column would read as "1.00". If
the Complete column was any date sooner than the Target date, the
Metric would be higher than "1.00"; for a Complete date later than the
Target date, such as 04/06/2011, then the Metric would be under than
"1.00"

Target = K4 (mm/dd/yy)
Complete = L4 (mm/dd/yy)
Metric = M4 (0.00%)

My metric targets may assist in articulating my request:
Marginal : metric less than .90
Review : metric between .90 - .93
Effective : metric between .94 - .97
Good : metric between .98 and 1.00
Outstanding : 1.00 plus 10% of commitments delivered ahead of
schedule