Craig Edwards released an excellent series of articles this morning about prospect valuation.
Using historical data from Baseball America lists as a base, the first article attempts to attach a WAR figure to each player inside the top 100 (50+ FV players) in order to determine surplus value through the first nine seasons of a career. The article explains the methodology used in more intricate detail.
Spoiler alert: Vlad's prospect value is $112M - $47M higher than second-place Fernando Tatis Jr.
https://www.fangraphs.com/blogs/an-update-to-prospect-valuation/
The second article in the series attempts to determine a value for the prospects with a future value of at least 40 but below 50.
https://www.fangraphs.com/blogs/putting-a-dollar-value-on-prospects-outside-the-top-100/
Now that the approximate values have been established, we can move on to ranking the farm systems. Craig applies his data to each organization to determine the value of the approximately 500 40+ FV players in the minor leagues. His purpose is to come up with a ranked list of each farm, one through thirty.
Spoiler alert: Toronto is 5th with a value of $298M. That's right, butt-chug a bag of dicks, Keith Law!
https://www.fangraphs.com/blogs/post-2018-farm-system-rankings/