WARNING! Statistically heavy post follows...
Tychus said:
I don't have all the numbers in front of me at the moment, but it ought to be pretty simple to crunch the probabilities of survival+promotion for each career to see if there are any "sweet spots" for skill gain.
It looks like the careers with 6+ Survival and Advancement targets are the best "sweet spots".
Since 4 in 5 characters will have at least one characteristic bonus of +1, and 1 in 3 will have two, the best plan of action is to place these in the characteristic pertaining to Survival first, and (if fortunate enough to have two) Advancement second.
This gives a survival chance of...
83% of surviving 1 term
69% of surviving 2 terms
57% of surviving 3 terms
48% of surviving 4 terms
40% of surviving 5 terms
33% of surviving 6 terms
The chances of Advancement are the same as above if there is a second characteristic bonus of +1, or the following with no bonus...
72% of gaining 1 promotion
52% of gaining 2 promotions
38% of gaining 3 promotions
27% of gaining 4 promotions
20% of gaining 5 promotions
14% of gaining 6 promotions
So assuming an average character with a single characteristic bonus of +1 in a career with 6+ S&A, they could with an evens chance survive four terms and gain Rank 2. If this is a Military man, it produces a character with 6 rolls on the skills table and 2 bonus skills attached to Rank.
Taking the 1 in 3 characters with two characteristic bonuses of +1, they will on an evens chance survive four terms and be promoted four times. Granting them (if military) 8 rolls on the skill table, 3 bonus skills attached to Rank, and an extra roll on the mustering out table.
Using the same characteristics for a doctor with a 4+/8+ S&A, would produce on an evens chance a character with 8 terms service, who'd never be promoted (if only one bonus characteristic) or once (if two bonus characteristics). However, since the Advancement roll also hides the 'roll more than number of terms served or leave the service' rule, the doctor would actually on average only serve 6 of those 8 terms.
Therefore the doctor with one +1 characteristic bonus would have 6 rolls on the skills table and none from promotion. Whereas the doctor with two +1 characteristic bonuses would have 7 skill rolls, and 1 bonus skill attached to Rank. Neither would receive an extra mustering out benefit. Academics, Entertainers, Drifters and X-Boat pilots will be even more heavily penalised, since they have significantly less chance of ever being promoted.
Thus the 6+ S&A careers usually give an extra two or three skills - which is a considerable advantage. Of course, this is only taking average rolls into consideration. Characters with 6+ S&A who possess even better characteristic bonuses, or who roll only slightly above average for their survival and advancement, or (cringe) both, will gain disproportionately more skills and benefits than those with a 4+/8+ (or worse) S&A!
The probabilities are primarily skewed because of the 2 point steps between different career's survival and advancement target numbers. Changing them from 4+, 6+ and 8+, to 4+, 5+ and 6+ instead would reduce (but not eliminate) that bias.
I hope this helps!