Through my research on innovation, pricing, and quality, my goal is to drive positive change in health care. I was the lead author of two articles that became law. 

Priority review vouchers

I was the lead author of a 2006 article proposing the priority review voucher program to encourage innovation for neglected diseases (Ridley et al. 2006). Thanks to collaboration with US Senators, the law was enacted in 2007. The FDA has awarded more than 60 vouchers and vouchers sell for about $100 million each, so we created a multi-billion dollar market and encouraged new life-saving drugs. For more information about the program, please visit the voucher page.

Pharmaceutical shortages and quality

We document that low and inflexible prices are associated with shortages (Ridley et al 2015; Yurkoglu et al 2017). Shortages could be rarer if prices for the oldest drugs and vaccines were higher and more flexible. Alternatively, we can accept occasional shortages and mitigate the harm through rationing, which was a successful strategy with the Hib vaccine (Liebman et al 2023). We also examine efforts to ensure drug quality by regulators (Cuddy et al 2023) and businesses (Ridley et al 2006).


Government policies play a pivotal role in shaping drug launch prices and price changes. We delved into the relationship between Medicare reimbursement and drug launch prices (Ridley and Lee 2020), as well as the regulation of price increases (Ridley and Zhang 2017). We also proposed a simple tool for forecasting market share in the US pharmaceutical market (Régnier and Ridley 2015).


There are many mechanisms available to government agencies seeking to promote drug development for otherwise neglected diseases. One mechanism is a prize such as the aforementioned priority review vouchers (Ridley et al 2006). Another mechanism is direct funding of research by government agencies. However, we show that across countries, some governments free ride, diverting funds to other diseases and purposes (Kyle et al 2017). Another mechanism is a transferable exclusivity voucher in which a drug developer is rewarded with longer market exclusivity for a different drug. However, exclusivity delays generic entry and thus delays savings. We show that if governments and insurers pay almost all of the costs of the most expensive drugs, though, then exclusivity vouchers are not so different from direct government funding (Boyer et al 2022).

Vector expedited review vouchers

Building on the success of the priority review voucher, we proposed vector expedited review vouchers (Ridley et al 2017). Our proposal became law in 2022. The aim of the program is to encourage innovation for the products that stop disease-carrying vectors, like mosquitos. Under the program, the maker of a pesticide to treat bed nets receives a voucher for faster regulatory review at the US Environmental Protection Agency for a different product.


When businesses cluster, they engage in more intense price competition. So why cluster? We show that followers cluster near leaders to i) free ride on the demand information of the market leader (Ridley 2008), ii) because they can differentiate their products and mitigate price competition (Picone et al 2009), and iii) because zoning forces clustering (Ridley et al).

For more information, see my Google Scholar page.