Prioritise re-directing donations

There are many, regular, large, charity fundraising events. Examples include the UK's Red Nose Day (approx 40 million USD a year) and the Channel Seven Perth Telethon (approx 50 million USD a year).

A one-off intervention to redirect the funds raised by these events towards more cost-effective charities could have large, long-term benefits. 

As these could plausibly be one-off interventions, the long-term return on investment of these efforts could be extremely high - Red Nose Day has raised over 1 billion USD over the last 30 years.

As a first step, existing donors could approach fundraisers like these with evidence on charity cost-effectiveness, and recommendations for prioritising charities which are both highly cost-effective and meet the priorities of these fundraisers.