2) Regarding the computation of the risk score: If you only use confirmed cases with voluntary sign up, you might not get enough data; if you use suspected cases by symptoms, you will get a lot of false positives due to worried people with the flu. In the absence of data on how to properly account for that, this is a very difficult problem.
These are significant challenges and I talk a bit about how they can be addressed in The Incentives Align and at the end of the section Example App Questionnaire. I imagine there would always be more confidence put in a confirmed case with a code than someone who just answers yes to having cold or flu symptoms recently.
Also, for confirmed cases, as part of contact tracing, the CDC sometimes identifies a site of concern where a patient might recall that something particularly infectious happened before they were aware they were sick. For example: “Oh. I remember that a few days ago, I sneezed quite forcefully and unexpectedly at my favorite buffet, so I couldn’t cover my nose. Oh, and then again on the way home on the BART! I’m so sorry.” Tracing multiple paths backwards, you might get a lot of data from a single event.
These are significant challenges and I talk a bit about how they can be addressed in The Incentives Align and at the end of the section Example App Questionnaire. I imagine there would always be more confidence put in a confirmed case with a code than someone who just answers yes to having cold or flu symptoms recently.
Also, for confirmed cases, as part of contact tracing, the CDC sometimes identifies a site of concern where a patient might recall that something particularly infectious happened before they were aware they were sick. For example: “Oh. I remember that a few days ago, I sneezed quite forcefully and unexpectedly at my favorite buffet, so I couldn’t cover my nose. Oh, and then again on the way home on the BART! I’m so sorry.” Tracing multiple paths backwards, you might get a lot of data from a single event.