I'm 100% sure my signature from more than a decade ago when I last signed paperwork for a new license doesn't match my current handwriting/signature. Also, I'm

I'm 100% sure my signature from more than a decade ago when I last signed paperwork for a new license doesn't match my current handwriting/signature. Also, I'm under the impression that signature verification isn't a very sturdy science. I'm curious what the false positive/false negative rates are and what variables are likely to affect them.