Argument Dilution Effect

Arguments don't add up - they average out.

Example...

• People were willing to pay less for a new dinnerware set when the set was actually larger but also included some broken items(Less is better effect).
• In medical ads, side effect of stroke, heart attack is considered more dangerous than side effect of stroke, heart attack and itchy feet.

If you have two strong arguments and a weak one for your cause, it might be better to omit saying the weaker argument because it will dilute the total argument.