Small Scale Local Interventions: A Cost-Effectiveness Analysis of Passing Sunscreen at Outdoor Events
Backstory
I recently was at a music festival, where we stood in a long queue in the scorching sun. The festival would go from around 10 am to 10 pm and all stages were outdoor with practically no shadows to be found. My group had another person besides myself with sunscreen and I decided on passing my sunscreen backwards to the group behind us who didn’t bring any, with the comment that they should continue passing it on afterwards. I did that just because it felt nice to do; a small act of good, but when thinking about it I became pretty sure that this is much more cost effective than typical interventions in rich countries.
I spend a few hours reading up and calculating likely cost effectiveness of this action and am now pretty certain that it is less cost effective than the best global health interventions like de-worming and malaria treatment and prevention, but I’m also quite certain that it is in the same order of magnitude.
I want to use this example mainly to spark a discussion about the general category of local interventions like this. Not scalable, but maybe cost effective on a small scale and therefor overlooked. Here is an analysis with calculations for the sunscreen example.
1 Sunscreen
1.1 Idea
1. Buy the cheapest moderately high SPF sunscreen (while avoiding fake products).
2. Write “please pass me along when finished” on the sunscreen.
3. Take it to an outdoor event, with queue, where people are likely to be in the sun for a long time.
4. Pass it along behind you.
1.2 Sources of good
The direct sources of good are:
1. Less pain and annoyance from sunburn.
2. More enjoyment at the event.
3. Less skin cancer.
1.3 Calculation
This was pretty difficult to do and I expect it be very high variance, I expect I’m wrong by around a factor of 3 in the first 2 categories and gave up on the full skin cancer calculation.
As far as I saw there is no paper with clear listed stuff like “lifetime risk of skin cancer per sunburn”. Only information fragments scattered across the internet. I did finish a very rough estimate of effectiveness gained from prevention of melanoma fatalities, but I could well be wrong there by an order of magnitude. I did not count fatalities from non-melanoma, or loss of life quality or cost for treatment for either melanoma or non-melanoma.
The first relevant calculation is how many units of sunscreen you get per dollar, then how much protection each dose is expected to give from sunburn. Then the consequences of the sunburn can be calculated as pain/annoyance and skin cancer. Additionally loss of enjoyment at the event can be calculated from an estimate of people who avoid the sun at the event, in order to not get burned. I list sources and considerations in this sheet. You can adjust your own best guesses for the inputs. I also included a screenshot here:
I got 250$/daly in the end. In comparison malaria treatment costs around 150$/daly and is currently rated among top causes (link).
1.4 Discussion
This intervention seems to be very cost-effective but less so than top treatments. There are additional benefits not included like non-melanoma fatalities prevented and loss of life quality even from effective treatments, but it might be that GiveWell does also not include such metrics (feedback on what GiveWell typically includes would be appreciated) .
The biggest reason why it might still be worth it even though it is not the most effective one is if you do it from your non-EA budget, given that it is tangible, might give you a nice feeling and look good in front of your friends :D
Maybe some people even ask you how you got the idea and you can explain what EA is about without barging in with the topic yourself.
There are other reasons like people feeling better about society, but at this point it feels like I’m reaching to make the idea look better in my eyes than it warrants.
A way to scale this up to a slightly larger scale endeavor, would be to place dispensers at beaches (maybe ones you can’t remove and that have a few seconds delay between servings so people can’t go there and just fills up their own tube). An advantage would be that you can scale the costs down a lot for cheap sunscreen in bulk.
2. Conclusion
I hope this example served as a good illustration of a possibility for small scale local EA and hope that you have other ideas that might be high impact on a small scale!
I’m sure I made some mistakes and I’m happy for feedback to learn from them.
Update
Based on Stan Pinsent’s comment: I added a DALY estimate for melanoma case, based on vizhub.healthdata, which I adjusted downard a bit (reason explained in table). It still pushed my DALY/melanoma case from 0.8 to 2.5.
Based on NunoSempere’s comment: I adjusted sunburn risk without shared sunscreen down from 30% to 20%.
Based on Ellie’s comment: I added a multiplier in the table for possible tax deductions, in the current table it’s at 1, so does not influence the calculation.
In total $/DALY changed from 250 to 240.
Updated sheet from ods to google sheets here.
Upvoted for making an actual calculation with reasonable numbers.
I’m so with you, I think we should continue to encourage botecing nearly every new cause idea. It’s a great starting point for discussion and improvement. Having a spreadsheet like this encourages me to look into it in more depth and give feedback ( which I’ll do later) rather than just reading she moving on.
Nice!
Two comments:
Sunburn risk without shared sunscreen seems a bit too high; do 30% of people at such concerts get sunburnt?
I recently got a sunburn, and I was thinking about the daly weight. A DALY improvement of 0.1 would mean prefering the experience of 9 days without a sunburn over 10 days with a sunburn seems… ¿reasonable? But also something confuses me here.
Initially I thought this was unreasonably high, since e.g. lower back pain has a disability weight of ~0.035. But if we try an estimate based on GiveWell valuing 37 DALY as much as 116 consumption doublings, preventing the loss of 0.1 DALYs would be equivalent to a ~24% increase in consumption for 1 year. Daily, it would mean ~$20 for a person making $30k/year. This seems surprisingly reasonable for sunburn, given that I don’t think these numbers are meant to be used this way.
I wonder if this equivalence of ~24% income per 0.1 disability weight is totally off (as many of these things are clearly non-linear), or can be used for similar estimates.
Thanks for the feedback! About the comments:
I skipped over a factor there: I expect 1/2-2/3 of people to already have sunscreen in their group and likely using their own instead of a random one given by a stranger (probably also somewhat lower quality as we bought a generic brand for in this calculation). But whoever does not use the sunscreen is also not part of the cost calculation. The 30% is the sunburn risk of those who would use the shared sunscreen. If my 1/2-2/3 having sunscreen in their group assumption is correct and 30% of those that do not get a sunburn, you would expect 10-15% of people to have a sunburn at the end of such an event, of those being there early with you in the queue. Lots of people also come later in the evening, which decreases the fraction of people with sunburn you’ld see further.
I might be a bit off here, but the 0.035 for lower back pain seems a bit low. I think most people offered to have another day in the month but lower back pain the whole month would decline. On the other hand I’m pretty sure that most people with lower back pain would take the trade the other way. I also found this for GBD 2017, which would be a mean DW across the varieties of low back pain of around 0.11. The 0.035 would seem like a reasonable weight for the median “back pain” but not for the mean including more severe cases which is closer to my association with the term “low back pain”. Table in the link:
Yeah, good point; on the back of my mind I would have been inclined to model this not as the sunscreen going to those who don’t have it, but as having some chance of going to people who would otherwise have had their own.
True, I think I’ll change the 30,50,20 (would be sunburned, would have gotten it elsewhere, would have stayed in shadow) to 20,60,20 (would be sunburned, used own or gotten elsewhere, stayed in shadow).
Interesting! This actually reminded me of a flower farmer I interviewed 4 years ago as part of my masters thesis and the reason why I was interviewing him was that he had no (third party) “social certification” for his flower production but brought up giving sunscreen to his employees which no other farmer that I interviewed (including the ones with social certification mentioned) did. Unfortunately I wasn’t able to prioritize the issue as part of the other things I was assessing, but it did leave me thinking (a lot!).
Nice, this is fun to read!
From a quick check on the Global Burden of Disease Survey (GBD) [https://vizhub.healthdata.org/gbd-results/], restricting to wealthy countries, we get the burden of melanomia to be 73.34 DALYs per 100,000 (counting both death and disability) and the incidence to be 19.19 per 100,000 per year . So the burden per case of melanomia is 73.14/19.19 = 3.8 DALYs.
This gives a higher estimate for the impact of the intervention on cancer, as you are essentially using 10*0.08 = 0.8 DALYs per cancer case.
I expect “the extent to which preventing a sunburn reduces cancer risk” is the most unknown quantity, however.
Thanks, that is really useful information!
I think I’ll wait for a bit more feedback to come in and then update this post with the new information.
If you’re an American, you can buy suncreen using your tax-free FSA—which brings the cost down ~10-40% depending on your tax bracket.
I just wanted to add that I’ve been at events in The Netherlands where sunscreen manufacturers were giving away free sunscreen (either by people or in dispensers) so the cost was zero (it was basically marketing by sunscreen brands).