I’d prefer not to share my actual scores because it’s hugely subjective and might cause a riot, but I can tell you a bit of the process.
There are a number of reasons why people don’t get a five star silent assassin rating. I imagine a lot of players have a more casual relationship with the game and they just like to try a contract, go with whatever happens, then move on. Other players will replay it a few times and eventually get it or give up. Similarly, players get SA rating if the contract was easy or they persisted. Then this is complicated because “easy” becomes subjective, depending on your skill level.
So I went through a load of other featured contracts and noted the number of people that had played them versus the number who had obtained a five star silent assassin rating. I felt that there was some correlation between the proportion who achieve SA and the difficulty. Or was this more to do with how interesting the contract was?
I tried to find good matches between my candidates and current featured contracts and used that as some type of index. This was only a partial indicator.
The main indicator, however, was based on my personal knowledge of the maps. I had an opinion of which sections of which maps and targets that were going to be challenging or easy. Each target received a rating. Obviously this is quite subjective. By taking into account that contracts requiring you to string together more successful take-downs would increase the overall difficulty, this allowed me to get an overall score.
However, as I explained in my post above to @_AnoMade, I was looking for contracts that could be played by two types of player: skilled and casual. Skilled players will quickly figure out a good route and replay it over and over to optimise and produce insanely good times. Yet if the balance of targets was right, then more casual players would not be completely put off by just missing out on SA on their first run and would be encouraged to retry until they get it.
So this further complicated the difficulty rating because if you take your time and use a cautious approach, then it might be seen as an not too difficult. But to use Prostate Exam as an example, if you want to get a crazy good time, then it’s a tricky contract.
Bottom line, though, my main criteria for selection was ensuring a good balance of location and contract type. The difficulty index had some influence on my interpretation of contract type.