Separate activity from outcomes.
Letters dropped describe the work done. Leads and clients describe what followed. Keep those counts separate.
Use the same denominator.
Leads per 100 letters = linked leads ÷ letters dropped × 100. If 48 letters bring 2 linked leads, that is about 4.2 leads per 100 letters. This is an illustration, not a promised result.
Give responses time.
Record when the work happened and when the reply came. A small sample or a short observation window can mislead.
Ask the next question.
After a visit, record whether the lead became a client. Return to a plaza because the linked outcomes justify the work.