You blame the architect, who didn't adequately cook in automated test cases to catch data integrity bugs.

What is the point of this?

I'd think the data analyst is to blame here, since he is the person which sole purpose is to know right data from wrong data.

I'd like to know the point of this but I blame everyone. The front-end for making the error, the back-end dev for not following-up after identifying the problem, and for not having tests in place that would have avoided the problem, and of course the data analyst for forgetting to look at the problem.

I'm with you. Look past blame, and evaluate the causes behind the failure as a collectie in order to examine ways to ensure that the problems aren't repeated in the future. Blame perpetuates ego in group programming. Possessing an ego while dealing with a distributed project like this gets you further from the reality of things and makes it harder to prevent errors.

This seems to really be an exercise in futility because at any real job, they would all be "blamed" for screwing up. If I had to pick one person to fire though, it would be the front-end developer I guess because he caused the issue to begin with.

What happens if the change by the frontend developer enormously benefitted the users? Everyone was happier, except for the people collecting data...