A few scouting-based publications have recently published midseason top 50 prospect lists (namely Baseball Prospectus and Baseball America), a bright spot in the dog days of summer for fans of teams with poor major league clubs but elite collections of prospects.

It's easy for fans to expect stardom, even immediate stardom, from their top prospects, but history tells us these expectations are largely unjustified, with the exception of a few elite talents.

What should we expect from midseason top 50 prospects? Should Cubs fans expect Kris Bryant, Javier Baez, and Addison Russell to become superstars? How about simply useful major league players? What are the chances that one or more provide little to no value at the highest level? Finally and perhaps most importantly, what will be the immediate impact of these Top-50 prospects?

To answer these questions, I looked back at the Major League contributions of Baseball Prospectuses top 50 prospects from three years ago (list can be found here). Three years is a lot of time for a prospect, especially a highly regarded prospect, to establish some value at the Major League level, so by examining this list of players we can establish a set of expectations for the current midseason top 50 based on a recent historical comparison.

It should be noted that not all players on the 2011 top 50 have debuted, but I would argue that the reason why most of these players have yet to debut is a lack of development, causing them to fall down prospects lists and out of favor in their organizations. Bryce Brentz, Mike Montgomery and Gary Brown fit this bill, but there are a few exceptions, namely Miguel Sano and Jameson Taillon, who remain top prospects but have yet to debut due to Tommy John surgery.

Average Contributions

The 50 players on the 2011 BP top 50 prospect list have combined for 118.2 Wins Above Replacement (all WAR totals according to Baseball-Reference), which leads of an average of a mere 2.36 per player. Considering the hype surrounding these players, this seems low, although all of these players spent at least part of these three years in the minor leagues (status as a current minor league player was required for the list).

Projecting stardom is even more dismal. Only 10 of the 50 players have made it to an All-Star Game, including the upcoming game in Minnesota, and only two have appeared in more than one. Again, that is a low total and shows that projecting All Star caliber seasons from young players is a largely a fools errand.

However, not all top 50 prospects are created equal. There's a reason why Bryce Harper was the top prospect on this list, and why Gary Brown came in at number 47. Keeping this in mind, here are those same statistics separated to account for placement on the list.

From this sample, the value of top 10 prospects relative to the value of the rest of the prospects is very apparent. The top 10 prospects have averaged 5.3 WAR during the three years immediately following this ranking, which is the equivalent of either one all star campaign or two-and-a-half seasons as an average regular. That's very good value and worthy of the hype often surrounding them, although value drops off significantly after that.

Prospects in the 11-20 range produce just over half as much value per player than the top ten prospects, a moderately respectable 2.97, but then the list becomes barren. The average WAR figure is almost cut in half again as we move to the 21-30 range, then drops below one for the remainder of the list. Pitting the top ten against players in the 31-50 range, the former group has produced five times more WAR than the latter.

The distribution of All-Star Game appearances among the top 50 prospects is close to what we would expect, with the exception of number 41 prospect Jean Segura and number 42 prospect Jose Altuve combining for three selections. Apart from that, stardom is predictably found most often among top 10 prospects, as those 10 players average a very high 0.5 All-Star Game appearances within three years of the publication of the list.

Per-Player Data

I've listed only averages thus far, but to get a complete sense of the chances of these prospects to make a useful contribution within the next three years it is useful to examine the numbers on a per-player basis. In the chart below, the numbers represent total players that fit the criteria in each column. Some players, such as Bryce Harper and his 8.6 WAR, are listed more than once as Harper has produced greater than 0 WAR, greater than 2 WAR, and greater than 5 WAR. The same premise holds true for All-Star Games as both players who have been to two All-Star Games are included in the “>= 1 ASG” column.

The takeaways from this chart are quite similar to the takeaways from the previous chart. Of the top 50 prospects, 30 have debuted and played above replacement level (0 WAR), including 8 of the top 10. The list drops off after that and plateaus at five of the 10 players in the bottom two groups. The difference in total players making a positive contribution is not as substantial, but greater differences begin to arise as we increase the levels of contribution across the chart.

Of the 30 players to make a positive contribution, 19 have contributed at least 2.0 WAR, or roughly the equivalent of one season as an average regular. Included in this number are 8 of the top 10 prospects, which accounts for just under half of the total.

The bottom 30 prospects on this list are especially weak, as only six players (20%) have posted at least 2.0 WAR within three years of being named to this list. For all the hype surrounding prospects these days, the value for players outside the top 20 names is relatively minimal. There are impact players at the top and few contributions of much value after that.

Moving over one more column, this point is confirmed once again. Half of the top 10 prospects have produced at least 5.0 WAR, the same total as the entire rest of the list. Players at the top are not only the most likely to contribute, but in this list, the players in the top ten have been just as likely to become above-average contributors within the first three years as the rest of the list combined.

The chances of a prospect becoming an All-Star follow the same trend. 10 players have combined to attend 12 All-Star Games, and four of the players in the top 10 combined to make five of those appearances. Jose Altuve prevents this list from being too top-heavy, but the trend remains clear.

Mid-Level Prospects Are Not Worth the Hype

While this only covers one class of prospects over a three year period, the results of this analysis are very clear. Relative to the rest of the list, top ten prospects have substantially more value over the first three years than one would expect.

Due to the limitations of the study and fact that we are now dealing with an entirely different crop of prospects I cannot give you exact figures, but top ten prospects, over the first three years since their inclusion in the lists, are at least one and a half times more valuable than prospects in the 11-20 range. Additionally, top 10 prospects are roughly 2.5 to 3 times more valuable than prospects in the 21-30 range, and 4 to 5 times more valuable than prospects in the 31-40 and 41-50 ranges.

What does this mean? For one, it helps to establish trade value for prospects based on ranking. The Cubs recently acquired consensus top 10 prospect Addison Russell, who, based on the values found in this historical comparison, is worth as many as five back-end top 50 prospects by himself. The Cubs also acquired Billy McKinney, who isn't a top 50 prospect, and has minimal value relative to Russell.

These ratios also tell us about the ideal way to construct a system. While their depth has improved, the Cubs’ system is a bit top-heavy with Russell, Bryant, and Baez, but this study shows us that overcoming a lack of elite talent at the top of a system with depth is very difficult to do, as the value of top 10 prospects far outweighs the value of prospects even 20 spots down the list.