An Algorithm Told Police She Was Safe. Then Her Husband Killed Her.

so it’s probably just some points assigned for the answers and maybe some simple arithmetic.

Why yes, that’s all that machine learning is, a bunch of statistics :)

I know, but that's not what I meant. I mean literally something as simple and mundane as assigning points per answer and evaluating the final score:

// Pseudo code
risk = 0
if (Q1 == true) {
    risk += 20
}
if (Q2 == true) {
    risk += 10
}
// etc...
// Maybe throw in a bit of
if (Q28 == true) {
    if (Q22 == true and Q23 == true) {
        risk *= 1.5
    } else {
        risk += 10
    }
}

// And finally, evaluate the risk:
if (risk < 10) {
    return "negligible"
} else if (risk >= 10 and risk < 40) {
    return "low risk"
}
// etc... You get the picture.

And yes, I know I can just write if (Q1) {, but I wanted to make it a bit more accessible for non-programmers.

The article gives absolutely no reason for us to assume it's anything more than that, and I apparently missed the part of the article that mentioned that the system had been in use since 2007. I know we had machine learning too back then, but looking at the project description here: https://eucpn.org/sites/default/files/document/files/Buena practica VIOGEN_0.pdf it looks more like they looked at a bunch of cases (2159) and came up with the 35 questions and a scoring system not unlike what I just described above.

Edit: I managed to find this, which has apparently been taken down since (but thanks to archive.org it's still available): https://web.archive.org/web/20240227072357/https://eticasfoundation.org/gender/the-external-audit-of-the-viogen-system/

VioGén’s algorithm uses classical statistical models to perform a risk evaluation based on the weighted sum of all the responses according to pre-set weights for each variable. It is designed as a recommendation system but, even though the police officers are able to increase the automatically assigned risk score, they maintain it in 95% of the cases.

... which incidentally matches what the article says (that police maintain the VioGen risk score in 95% of the cases).