Not to answer my own question but I found the answer eventually. I think the best way is to use the M1 to M5 model developed by Coburn and Spence (1992)- Reducing Human Casualties in Building Collapse; Methods of Optimising Disaster Plans to Reduce Injury Levels. But any questions regarding this question please don't hesitate to contact me and I'll aid you if I can.  Alternatively if there is a better way I'd love to hear about it!

The following is the only paper I know of that quantitatively estimated the number of lives saved by mitigation.

Wyss, M., & Wu, Z. L. (2014). How Many Lives Were Saved by the Evacuation Before the M7.3 Haicheng Earthquake of 1975? Seismological Research Letters, 85(1), 126-129. doi: 10.1785/02201 30089

I have proposed to calculate the number of lives saved by retrofitting by first calculating the fatalities in a realistic scenario earthquake with the old building fragility and then with the new fragility to estimate the difference. But we have not been funded.

Thank you for your answer Mr Wyss. I am very sorry to hear you have not been funded as your paper is very interesting. I recently completed my dissertation entitled: 'Assessing Seismic Risk Reduction in the Kathmandu Valley using Cost-Benefit Analysis to Evaluate Loss Prevention in Schools' which utilised Coburn and Spence's methodology (1992) to estimate how many lives can be saved due to different methods of mitigation. If you are interested then it can be downloaded from my publications. I am considering adapting it for publication so any advice you have would of course be more than appreciated.

Good luck in your future work. All the best,

Nick

I would be interested in reading your manuscript that you plan to develop from your thesis. Could you perhaps send me that paper by Coburn and Spence or tell me where I can download it from

thanks

max