The Impact of Age on Prospect Success Rates

In previous posts, I’ve written about Baseball America’s success rates predicting which prospects will succeed in the majors. In this post, I want to write about their success rates when taking age into account from 1990-2006. 

In order to determine how successful Baseball America has been at predicting success of prospects based on age, I downloaded all the data for all rookies who had a season of at least 100 PAs or 25 innings in the majors and split them into groups based on whether they were a ranked Baseball America Top Hundred prospect, whether they were a position or pitching player and based on their age when they first entered the majors. The age groupings are 20-22, 23, 24 and 25+. There were very few players that made it to the majors before 20 and all of them were ranked so I didn’t include them in this analysis.

As in previous posts, a successful prospect is one that is worth at least 1.5 WAR per year for his first six years.  If a player doesn’t have at least 100 PAs or 25 innings in the majors his first year than that year is omitted from the calculations (but is still considered the year he enters the majors). If a player doesn’t have at least 100 PAs or 25 innings in either of his first two years than both of those years are omitted from the calculations. His third year is included regardless of whether he has at least 100 PAs or 25 innings.

The first prospects I looked at were position prospects ranked by Baseball America. The following table shows their success rates.

Age  Group	Year Group	Success    Percent	Number of Successful Prospects
20-22	1990-1993	42.59%	23
20-22	1994-1997	48.89%	22
20-22	1998-2002	31.03%	18
20-22	2003-2006	56.52%	26
23	1990-1993	39.39%	13
23	1994-1997	33.33%	5
23	1998-2002	44.44%	12
23	2003-2006	33.33%	9
24	1990-1993	43.75%	7
24	1994-1997	7.69%	1
24	1998-2002	20.69%	6
24	2003-2006	38.46%	5
25+	1990-1993	16.67%	1
25+	1994-1997	18.18%	2
25+	1998-2002	40.00%	4
25+	2003-2006	11.11%	1

The majority of successful offensive rookies ranked by Baseball America are between ages 20-22 when they first play in the majors and have the best success rates. Offensive prospects that don’t make it to the majors until they are 23 or 24 still have high success rates. Offensive players ranked by Baseball America that do not make it to the majors by 24 have lower success rates. 

The following table looks at unranked offensive prospects and their success rates:

Age Group	Year Group	Success Rate	Number of Successful Prospects
20-22	1990-1993	3.70%	1
20-22	1994-1997	13.04%	3
20-22	1998-2002	17.86%	5
20-22	2003-2006	19.35%	6
23	1990-1993	13.16%	5
23	1994-1997	5.56%	2
23	1998-2002	7.14%	3
23	2003-2006	11.11%	3
24	1990-1993	6.67%	4
24	1994-1997	13.33%	6
24	1998-2002	12.24%	6
24	2003-2006	15.56%	7
25+	1990-1993	4.72%	6
25+	1994-1997	3.95%	3
25+	1998-2002	6.90%	8
25+	2003-2006	6.25%	6

The number of successful prospects remains similar by age but the chance of an unranked prospect succeeding decreases as he becomes older. It is far less likely that an unranked offensive prospect will succeed than a ranked one. Unranked prospects that make it to the majors by 22 have a surprisingly high chance at being successful.

The following tables show the number of successful hitting prospects by rankings.

Age	Year	1-10	11-20	21-30	31-50	51-100	Not Ranked
20-22	1990-1993	9	7	1	2	4	1
20-22	1994-1997	6	6	3	4	3	3
20-22	1998-2002	7	2	1	6	2	5
20-22	2003-2006	6	7	3	5	5	6
23	1990-1993	2	2	1	6	2	5
23	1994-1997	1	2	0	0	2	2
23	1998-2002	1	3	1	4	3	3
23	2003-2006	3	0	1	2	3	3
24	1990-1993	2	0	1	2	2	4
24	1994-1997	0	0	0	0	1	6
24	1998-2002	0	0	0	1	5	6
24	2003-2006	0	0	1	0	4	7
25+	1990-1993	0	0	0	0	1	6
25+	1994-1997	0	0	0	0	2	3
25+	1998-2002	1	0	1	1	1	8
25+	2003-2006	1	0	0	0	0	6

Age Group	Year Group	Not Top Hundred	Top Hundred	Success Rate
20-22	1990-1993	1	23	95.83%
20-22	1994-1997	3	22	88.00%
20-22	1998-2002	5	18	78.26%
20-22	2003-2006	6	26	81.25%
23	1990-1993	5	13	72.22%
23	1994-1997	2	5	71.43%
23	1998-2002	3	12	80.00%
23	2003-2006	3	9	75.00%
24	1990-1993	4	7	63.64%
24	1994-1997	6	1	14.29%
24	1998-2002	6	6	50.00%
24	2003-2006	7	5	41.67%
25+	1990-1993	6	1	14.29%
25+	1994-1997	3	2	40.00%
25+	1998-2002	8	4	33.33%
25+	2003-2006	6	1	14.29%

It appears that Baseball America was better at identifying top talent aged 20-22 from 1990-1997 than it was in 1998-2006 but still ranked 80% of successful position rookies in that age group. While Baseball America accurately identified a large percentage of top offensive talent that entered the majors from ages 20-23, they were less able to identify top offensive talent that first entered the majors at 24 or older.  Many of the successful ranked rookies who entered the majors for the first time at 24 were ranked from 51-100. 

Another point worth covering is whether these trends remain true for both prospects that went to the majors after high school and those that went to the majors after attending college. This data can be found in a database created by Sean Lehman for all players that make it to the majors. Players that went to either a Junior College or Community College were excluded from this analysis because there were very few of them and the drafting rules for players at either of these are different than those drafted out of high school or a four year college.

This table shows the success rates of ranked offensive prospects based on whether they went to college.

Age Group	College	Success Rate	Number Successful
20-22	No	40.24%	68
20-22	Yes	59.26%	16
23	No	28.57%	16
23	Yes	47.50%	19
24	No	9.09%	2
24	Yes	37.78%	17
25+	No	15.00%	3
25+	Yes	31.25%	5

The majority of successful ranked prospects are those that go to high school and make it to the majors before they are 23 years old. Nearly all high school ranked offensive prospects that succeed make it to the majors before they are 24 years old. Younger high school ranked offensive prospects have a better chance of success than older high school ranked offensive prospects. 

While fewer college prospects between ages 20-22 make it to the majors than high school prospects aged 20-22 those who do have higher success rates than the high school prospects. Like high school prospects, younger college offensive prospects have better success rates than older college offensive prospects.  Unlike high school prospects, ranked college position prospects have good chances of succeeding no matter when they reach the majors.

This table shows the success rates of unranked offensive prospects based on whether they went to college or not.

Age Group	College	Success Rate	Number Successful
20-22	No	13.48%	12
20-22	Yes	21.43%	3
23	No	5.68%	5
23	Yes	13.95%	6
24	No	9.89%	9
24	Yes	13.48%	12
25+	No	4.67%	7
25+	Yes	6.87%	16

Unranked college prospects are more likely to be successful than unranked high school prospects. The earlier that both high school and college unranked prospects make it to the majors, the higher the chances that they will be successful.

Unranked high school offensive prospects are very unlikely to be successful if they don’t make it to the majors when they are 22 or younger. Unranked college prospects are most likely to be successful if they can make it to the majors when they are 22 or younger. Many successful college prospects were successful despite not reaching the majors until they were 24.

The above shows the success rate of offensive prospects based on age. Now, we can do the same analysis for pitching prospects. Here is the success rates for ranked pitching prospects:

Age Group	Year Group	Success Percent	Successful Prospects
20-22	1990-1993	20.00%	7
20-22	1994-1997	21.43%	9
20-22	1998-2002	44.26%	27
20-22	2003-2006	38.30%	18
23	1990-1993	28.57%	6
23	1994-1997	27.78%	5
23	1998-2002	34.62%	9
23	2003-2006	20.00%	4
24	1990-1993	16.67%	1
24	1994-1997	25.00%	2
24	1998-2002	10.00%	1
24	2003-2006	9.09%	1
25+	1990-1993	25.00%	2
25+	1994-1997	6.67%	1
25+	1998-2002	25.00%	2
25+	2003-2006	22.22%	2

From 1998-2006 most successful ranked pitching prospects made it to the majors by 22. The ones who did so had a good shot at being successful. Very few ranked pitching prospects succeeded if they didn’t make it to the majors by the time they were 23. While it looks like pitching prospects older than 25 succeeded at high rates, it is important to realize that those numbers are inflated by “prospects” that go straight to the majors such as Jose Contreras and Rolando Arrojo as well as low sample size. 

The next table shows the success rates of unranked pitching prospects:

Age Group	Year Group	Success Rate	Successful Prospects
20-22	1990-1993	22.50%	9
20-22	1994-1997	13.79%	4
20-22	1998-2002	6.00%	3
20-22	2003-2006	2.08%	1
23	1990-1993	2.63%	1
23	1994-1997	7.32%	3
23	1998-2002	11.11%	6
23	2003-2006	5.17%	3
24	1990-1993	10.17%	6
24	1994-1997	10.20%	5
24	1998-2002	5.00%	4
24	2003-2006	6.38%	3
25+	1990-1993	2.13%	3
25+	1994-1997	1.65%	2
25+	1998-2002	3.55%	5
25+	2003-2006	2.46%	3

From 1998-2006, Baseball America did a very good job identifying the top pitching prospects between ages 20-22. As a result, the vast majority of unranked pitching prospects failed regardless of age.  If this trend continues than very few unranked pitching prospects will be successful.

The following tables show the number of successful pitching prospects by their Baseball America rank or lack thereof.

Age Group	Year Group	1-10	11-20	21-30	31-50	51-100	Not
20-22	1990-1993	3	2	1	0	1	9
20-22	1994-1997	1	2	2	2	2	4
20-22	1998-2002	7	4	2	4	10	3
20-22	2003-2006	5	3	4	3	3	1
23	1990-1993	0	0	2	1	3	1
23	1994-1997	1	1	0	2	1	3
23	1998-2002	1	1	1	2	4	6
23	2003-2006	0	1	1	1	1	3
24	1990-1993	0	0	0	0	1	6
24	1994-1997	0	1	0	0	1	5
24	1998-2002	1	0	0	0	0	4
24	2003-2006	0	0	0	1	0	3
25+	1990-1993	0	0	0	1	1	3
25+	1994-1997	0	0	0	0	1	2
25+	1998-2002	0	0	0	2	0	5
25+	2003-2006	1	1	0	0	1	2

This table compares the number of successful top hundred prospects to non top hundred prospects.

Age Group	Year Group	Not Top Hundred	Top Hundred	Success Rate
20-22	1990-1993	9	7	43.75%
20-22	1994-1997	4	9	69.23%
20-22	1998-2002	3	27	90.00%
20-22	2003-2006	1	18	94.74%
23	1990-1993	1	6	85.71%
23	1994-1997	3	5	62.50%
23	1998-2002	6	9	60.00%
23	2003-2006	3	4	57.14%
24	1990-1993	6	1	14.29%
24	1994-1997	5	2	28.57%
24	1998-2002	4	1	20.00%
24	2003-2006	3	1	25.00%
25+	1990-1993	3	2	40.00%
25+	1994-1997	2	1	33.33%
25+	1998-2002	5	2	28.57%
25+	2003-2006	3	2	40.00%

Baseball America is really successful at projecting top talent from 20-22.  Baseball America has historically had very little success projecting talent that's 24 or older.

We saw earlier that from 1998-2006 that unranked pitching prospects have rarely been successful. The following table can show us whether these trends remain true for prospects that went to the majors after high school and those that went to the majors after college. 

Age Group	College	Success Rate	Total Successful
20-22	No	0.00%	0
20-22	Yes	5.26%	1
23	No	8.70%	6
23	Yes	8.10%	3
24	No	3.22%	2
24	Yes	7.40%	4
25+	No	3.54%	4
25+	Yes	3.01%	4

Very few unranked pitching prospects were successful from 1998-2006 regardless of whether they went to college or high school. There are roughly three successful unranked pitching prospects per year from 1998-2006. This table describing the performance of ranked pitching prospects based on whether they went to high school or college from 1998-2006 is more interesting.

Age Group	Year Group	College	Success Rate	Total Success
20-22	1998-2002	No	44.23%	23
20-22	2003-2006	No	42.42%	14
20-22	1998-2002	Yes	50.00%	4
20-22	2003-2006	Yes	30.00%	3
23	1998-2002	No	31.58%	6
23	2003-2006	No	14.29%	1
23	1998-2002	Yes	40.00%	2
23	2003-2006	Yes	27.27%	3
24	1998-2002	No	16.67%	1
24	2003-2006	No	0.00%	0
24	1998-2002	Yes	0.00%	0
24	2003-2006	Yes	20.00%	1
25+	1998-2002	No	28.57%	2
25+	2003-2006	No	33.33%	1
25+	1998-2002	Yes	0.00%	0
25+	2003-2006	Yes	16.67%	1

A plurality of successful pitchers go to high school and make it to the majors by 22. However, college pitchers that make it to the majors by 22 have similar success rates. Also college pitchers that reach the majors by 23 are more likely to be successful than high school pitchers that reach the majors by 23. Very few ranked pitchers older than 24 are successful.

To sum up, offensive prospects that went to college had a higher success rate than offensive prospects that went to high school regardless of whether they were ranked. However, the majority of successful offensive rookies did not go to college. The majority of successful pitching prospects also did not go to college and success rates for high school and college rookies were similar.

Baseball America was able to determine the best talent that reaches the majors before 23 with the exception of pitching prospects from 1990-1997. It successfully ranked 80% of successful offensive talent and 90% of successful pitching talent that made it to the majors before 23. Baseball America was much less successful at determining talent that makes it to the majors after 23.

Unranked offensive talent that made it to the majors by 22 had a surprisingly high success rate regardless of whether they went to college or not. So did unranked offensive talent that made it to the majors by 24 that went to college. This indicates that Baseball America could improve the accuracy of its projections by ranking more of these players.

Very few pitchers that made it to the majors that were 24 or older were successful regardless of whether they went to college or not. Baseball America was able to predict only one successful pitcher in this age bracket roughly every three years from 1998-2006. 

The majority of successful prospects entered the majors by 22. This indicates that age is more than just a number. The earlier a player reaches the majors the better his chances of success. Age has a definite impact on prospect success rates.