First let's see what dictionary said about "Slightly":

slightly adverb (SMALL IN AMOUNT)

I know 99% of people will say it's a chance. And they are right! But I think measures must be taken (including more complicated internal formulaes) to fix this:

Today in job with "Slightly Risky" tag on it, I have: 4 fails in 5 attempts (3 are IN A ROW) ... this is 80% fail rate!

Last month I have on same job 6 (SIX) fails IN A ROW from 8 attempts ... this is 75% fail rate.

Where did you see "Slightly"???? Where?

Also I have to mention something very weird: I have less fails when I was at like 100 Intelligence ... than I have now?!?!?!?!

I mean it's worse now!

Why?

Edited:

Today in job with "Slightly Risky" tag on it, I have: 5 fails in 6 attempts (3 fails IN A ROW; 1 success; 2 fails IN A ROW) ... and counting

Chance is under no contstraints when it comes to success or a fail. It depends as well on your global xp rate; which is hidden. (My job success rate to failure rate is pretty decent, now doing paste robbery. (I have 25 prestige levels thus far on my robbery/general jobs). Going from Intimidation > Fertiliser Robbery > Agave > Paste. (what i am doing right now).   

(Slightly risky) does not mean a 60-70% success rate. It's just a guideline as to what you can go for, and what to (generally) expect. 

You may have 4 fails in a row, then later in the day, it goes just swimmingly. Or you may get a few more fails. And a day or two here and there when it's a shambles and your questioning why your even doing the particular job in the first place. 

Only real time i get issues, is when i am 0% in a skill, from just prestiging. And i know when it ccomes to construction robbery, it's going to be a bit of a pain. 

I'm happy to have a discussion around whether we should put systems in place to limit 'luck' whether it be good or bad, but the descriptions are functioning correctly as it stands.