First even though the way they are calculated can be very different, in theory at least  I think the DALY should just be opposite of a QALY, so QALYs gained = DALYs averted (in practise roughly) for a given intervention

Thanks so much, I had the same question for my OneDay Health cost-effectiveness post and was unsure what to do.d

• In the "Doing good better" book they used I think 37.5 QALYs to a life but I'm not sure where they got that from (maybe using age discounting and like you say all life is not lived in good health?)
• For my OneDay Health calculation to be conservative I used 82 as close to the "global maximum realistic" life expectancy, which is where you take the life expectancy from a country like Hong Kong or Japan and use that. Now it's around 88 I think? The idea is that if every human is valued equally, this is the maximum realistic life expectancy given the best diet, medical care and other factors available 
• For DALY calculations now WHO uses 92, projecting out to 2050. "The loss function is based on the frontier national life expectancy projected for the year 2050 by the World Population Prospects 2012 (UN Population Division, 2013), with a life expectancy at birth of 92 years."

But with all that said I'm not very helpful as I don't have a clear answer for you ;). I could be wrong but I don't think there's a completely standard way of doing it.

I summarised a little bit how various organisations in the EA space aggregate QALY's over time here.

What I've been unable to find anywhere in the literature is how many QALYs a typical human life equates to? If I save a newborn from dying, is that worth 70 QALYs (~global life expectancy), 50 QALYs (not all of life is lived in good health), or some other value?

I think this post by Open Phil is probably related to what you're asking for and I would also recommend the GiveWell post on the same topic

I think this is still generally seen as a bit of an open question in the space

There's no single right answer here, and several good approaches depending on the application to which you want to put the information. A reasonable estimate is that a baby born today and then given the best life modern society can give it will accrue around 24 QALYs (at a 3.5% discount rate). This is equivalent to 70 undiscounted QALYs, but you absolutely must discount to some extent in this case, because a QALY now is clearly preferred to a QALY in 80 years time.

This value is found by multiplying the life expectancy of a baby born in the UK in 2020 by the typical quality of life that baby will experience each year of their life. Life expectancy is pretty straightforward to calculate (I take it from the Office for National Statistics), quality of life is  much more complicated - the standard in the field is Ara, R. and Brazier, J.E. (2010), but this is getting a bit out of date now.  https://eprints.whiterose.ac.uk/11177/1/HEDS_DP_10-11.pdf

Obvious problems with the translatability of this approach is that the Ara & Brazier paper only applies to the UK. Different countries will have different profiles of population health (which is obvious) and also different ways of interpreting how health applies to QALYs (which is less obvious). For example, if old age affects your ability to walk easily / comfortably then this might matter more to your QALYs in dense walkable European cities than car-focussed American suburbs (I have no idea if this mechanism is true, just giving it as an example). This will be particularly challenging if you're trying to calculate the number of QALYs a person accrues in a global health context, because there is limited research in the area.