Yes, but a program has many ways in which it cannot be correct, and eliminating one of them does not mean that you've eliminated a significant amount of problems, and it doesn't even mean that the amount of incorrectness you've eliminated is bigger if you'd spent your time with other approaches.

> The fact that you can make more general assumptions about pieces of code which you don't necessarily fully understand makes writing safer and correct code easier.

Except this does not seem to be the case, as evidence does not suggest that Haskell programs have significantly fewer bugs or are produced faster.

> Are you saying there have been studies that show Haskell's type system has not been correlated to higher correctness than say Java or Python, or are you saying you are unaware of any such studies?

I am saying that there is no evidence to suggest Haskell programs are more correct, and that at least one study has tried to find such correlation but did not.

> Also, Haskell's type system is certainly more expressive and strong than Java's or Python's.

It is, but it is still very weak.