Thank you for raising the profile of trusteeship as a volunteering opportunity. I agree that it's widely overlooked, and I think I have gained a lot from my past trusteeships.

Trustee boards are typically also short of resource, so increasing the pool of applicants is likely to be a good outcome. I'm glad you're doing this.

Other resources:

• I have used reach volunteering before and found it to be variable. It's run by volunteers (or was when I last used it) and the quality of the suggestions you get depends on the quality of your volunteers
• Other UK-based resources include...
• ... do-it.org ( https://do-it.org/channels/trustee-finder ) This site has traditionally been the primary resource for people in the UK looking for volunteering opportunities, although its history has been chequered of late, and the site hasn't always been up.
• ... small charities coalition ( https://www.smallcharities.org.uk/resources-trustee-positions/ )
• ... NCVO is the main sector body for the charity sector in the UK, and they have a site for trustee recruitment too: https://www.ncvo.org.uk/practical-support/information/governance/trustee-bank/vacancy-search

Some points on which skills people can use to add value:

• I think the charity sector's perceived skills shortage is in finance, which is both essential and the people with the right skills are scarce. (Source: conversations with many people in the sector)
• I'm not convinced that digital marketing is a top priority for the sector - for some charities their intervention may be about operating digitally, in which case this is more useful, although they are also likely to be the charities which already have this savvy. For fundraising, I'm doubtful that digital marketing is that useful in most contexts
• As a trustee, it's unlikely that you can add much value with project management skills, unless it's a very small charity. For medium to larger charities, a trustee should keep their involvement more strategic, so they wouldn't actively manage projects. Knowledge of Prince2/lean/etc may have some marginal value

Finally, I would question the value of the £500 estimate:

• The model does nothing to consider the variability in impactfulness of charities. Many people think that the majority of charitable interventions achieve nothing, and it seems odd to ascribe value to a charity whose work isn't achieving anything.
• Not only is the impact of the charity variable, so is the impact of the trustee. It's entirely possible for a key trustee to double a charity's impact or have no impact at all. Given that this is so variable, modelling this as a flat percentage seems like the model is glossing over a key input.

I think the biggest improvement would be correcting the fact that this model (accidentally, I think) assumes that improving any arbitrary high budget charity by 5% is equally as impactful as improving a Givewell equivalent charity by 5%. Most charity's impact is an order of magnitude smaller.

You could solve this with a multiplier for the charity's impact at baseline.

If I understand correctly, you figure that if you become a trustee of a £419668/year budget charity, if only you can improve the cost effectiveness by 5%, then you can divide that by 42 hours a year, to get £419668*5%/42 hours=£500/hour in the value of your donated time. (A style tip - it would be helpful to put the key equation describing roughly what you've done in the description, to make it all legible without having to go into the spreadsheet.)

I think it is fair to say that, were you to successfully perform this feat, you have indeed done something roughly as impactful as providing a £500/hour value to the charity you are trustee-ing for. So, if you improved a Givewell-top-charity-equivalent's cost effectiveness by 5% for a year, then maybe you could fairly take 5% of that charity's yearly budget and divide it by your hours for that year, as you've done, to calculate your Givewell-top-charity-equivalent impact in terms of how it would compare to donated dollars.

But if you improve a £419668/yr budget charity which is only 1% as cost-effective as a Givewell-top-charity-equivalent by 5%, then that makes your hourly impact 1%*£419668*5%/42 hours = £5/hour of Givewell-top-charity-equivalent impact - you'd be better served working a bit extra and donating 5 dollars to Givewell.

I don't think this model has credence even after these adjustments as I'm skeptical of the structure, but you did make those assumptions explicitly which is good. If you think the effect takes ~42 hours/year then this hypothesis is potentially cheap to just test in practice, and then revise your model with more information. Have you joined any boards and tried this in practice, if yes how did it go?

edit - ah, you're using the term "5% increase" very differently.

Instead it assumes a 5% increase, perhaps from £0 of impact to 5% of the annual income or perhaps from 100% of annual income to 105%

So just to be clear, this implies that making 100% of your annual income in impact would mean that you are the most cost effective charity in the world (or whatever other benchmark you want to set at "100%"). Used in this sense, the word "5% increase" doesn't mean "the shelter saves 5% more kittens" but that charity as a whole has gone from being part of the long tail of negligible impact to being 1/20th as cost effective as the most cost effective charity in the world. This isn't the way percents are usually expressed / this seems like a confused way to express this concept since the 100% benchmark is arbitrary/unknown - it would be better in that case to express it on an absolute scale rather than a percentage.

I appreciate the other comments about how the model does not take into account the base impact of the charities. Also:

1) Do trustees take on some form of legal responsibility for charities? If so, it could be risky to get involved with a charity you know little about.

2) Do you know how many other trustees are typically already involved? If you are one of three, I could see you having an easier time influencing a charity than if you are, say, one of seven.