So I've seen this topic coming up a lot lately, so I thought that it is time to get a sort of guide out there for job stat growth that outlines the fastest path if you are willing to forsake all other job specials for the sake of getting more job stats. I'll also post the drawbacks and advantages to each chosen option.

It's also important to note that if you're looking to make all stats grow in the same day it's either city jobs or being a director. A director gets ranges +5 to all stats thru +50 all stats from the ratings, it caps at 5* companies making +150 job stats a day as a director total. If you have 1 or 2 specific stats to focus on, with you can exceed this gain.

Option 1: Education job, should be no surprise. If you want a specific stat to grow, it grows at 100 for Manual or Endurance or 110 for Intelligence. Note: the specials require 10 job points, and top position gets 7 per day.   

Drawbacks: Needs 1500 Endurance & Manual plus 5000 Intelligence along with the time to get to the top job if you aren't already there. Weak specials

Advantage: It is free, at the cost of your job specials.  You get to choose how to distribute your job stat gain. 

 

Option 2: Buying Trains

It is important to note that each train is worth 50 primary and 25 secondary regardless of company type and job position.  So you buy  2 trains a day average that works out to 100 primary and 50 secondary job stats, that is significant. Odds are you can't buy all 10 that a 10* company will have. 

Drawbacks It is expensive.  You might not find a company that you want the specials for.  

Advantage: You can have friends who are directors help you out, and furthermore you may be able to choose a company that special you actually like. It is important to note. If you buy 5 trains a day that is +250 Primary job stat + 125 secondary job stats a day on top of the role gains.  Also important to note: if you are close to fitting in a role you could get rushed into the stat requirement for the role you are filling.  For example, a new player can apply at all the jobs that need under 2,000 primary and quickly get effective there due to training after 3 days at a company.

Option 3; buy a 10* company, have a friend run it and give you all the trains

Advantage: specials you want, highest stat gains

Drawbacks: expensive to buy specific companies, risk of getting scamed (it's legal), some employees may leave to get trains not all will though.

It is important to note that 2 player company types  has a boost to a job stat. It is a Lingerie Store and Clothing store. There are several of that company type. It gives +100 Endurance for 10 job points.... so it is the same as Education EXCEPT you can be in a 10 * company AND you can pay for trains at the same time. That means you can get +100 Endurance + a potential of 500 primary + 250 secondary job stats a day.  It is only 100 Endurance a day better than the other positions though, so per 10,000 Endurance you need it will save about 3 days (16.66 days vs 20 days for those interested) if buying all 10 trains.  If you buy 2 trains per day, it essentially halves the time as +100 Endurance is equal to 2 Primary Endurance trains.  Essentially: The more trains you buy the less valuable it is, but it is still significant. At going towards 100k Endurance it would save at least 33 days if starting from 0 Endurance. 

Edit: one thing that I should point out is that the general education bachelor degree makes education courses give a bit more job stats, but I personally can't recommend doing that first since it's such a small amount relative to everything else that provides job stats. There are many other education classes that make a better long term benefit. 

Editing edit: fixed a typo, added a few more things thanks to Wiber and Destroy for pointing out some details I missed.