What is uncertain, what is unknown and what can be modelled?
We can know, for a given classification, past grant rates. This gives a rough a priori probability.
We can also know abandonment and withdrawal rates.
We cannot know how an examiner is going to approach the case.
One of the biggest unknowns is the prior art that is cited. Prefiling searches enable a general view of the level and type of art that maybe cited. However, in my experience, prefiling search art is rarely cited in subsequent search and examination reports, everyone has a different set of preferred art to cite.
Generally there will be a link between claim length and novelty / inventive step objections: shorter claims are more likely to receive objections on these grounds.
We also cannot always know how valuable a patent will be. This depends on commercial context that is constantly changing.
We cannot know the outcome of litigation.
We can, though, update our probabilities based on events. For example, comments from an examiner, opposition board, Board of Appeal, or other party to proceedings can change our knowledge. A positive opinion can increase our estimate of the probability of success and a negative opinion can decrease the same.
Professionals that appear, externally, to be able to control uncertainty will attract more business. No one likes uncertainty, especially in business. However, even a rudimentary history or background knowledge would indicate that, although it is possible to be lucky, uncertainty can never be banished or controlled. Any offer of certainty is thus false.