Sabermetricians have long hammered home the mantra that stolen bases are an overrated offensive asset. An out is the most precious baseball resource, and the cost of running into one on the base paths far outweighs the relatively minimal value to be gained from thievery. In order to squeeze any benefit at all from steal attempts, therefore, they must succeed at a very high rate, which most teams throughout history have been unable to reach in any given season.

The rising tide of statistical analysis in baseball, however, appears also to have lifted the level of understanding about baserunning value, for we are now in the midst of the most efficient period of the modern era when it comes to swiping bags. The major league success rate on stolen base attempts rose each year from 2003 to 2007 and topped 70% in each of the past four seasons, a plateau that was reached in only three seasons between 1951 — the first year both leagues tracked caught stealing totals — and 2003. This current run of record efficiency represents the acceleration of a growing trend: Since 1951, stolen base percentage has risen steadily, while the per-team average number of attempts has fallen since its high in the 1980s:

PERIOD AVG. ATT SB %

1951-59 81 58.1

1960-69 108 62.5

1970-79 156 64.2

1980-89 178 67.7

1990-99 165 68.3

2000-07 151 70.2

In 2007, would-be thieves around the majors were successful on 74.4% of their attempts, by far the highest rate since 1951, breaking the record, set the previous season, of 71.4%. This year, base stealers have not been quite as efficient, but at 73.7%, the newly established level of heightened efficiency has been maintained.

Last year’s 74.4% figure was especially remarkable, not only because it was by far the highest in modern history, but because it meant that, for the first time since at least the beginning of the high-octane offensive era ushered in with the 1993 expansion, teams nearly broke even on the base paths. Statistical analyst Dan Fox has done extensive work at Baseball Prospectus evaluating baserunning, and using the run expectancy matrix he calculated that, between 2000 and 2007, the value of a stolen base averaged out to 0.17 runs, while getting caught took away half a run. Those figures lead to a zero threshold for stolen base success of just a little more than 74.6%. By that accounting, last year, major league teams were within five runs of coming out exactly even in terms of offense gained and lost through steal attempts.

Teams are now running less often than they did in the 1980s and 1990s — sensible, given that the modern offensive environment substantially decreases the value of playing for one run — and they are doing so with greater precision, picking their spots in order to better maximize offense. A more complete understanding of the cost of getting caught brought about by statistical analysis and the uptick in offense is likely part of the explanation for this, as are the ever-increasing speed, instincts, and athletic ability of today’s batters. Technology has probably also played a role: Players devoted to the stolen base can time each pitcher’s pickoff move and delivery to the plate and spend unlimited hours in that staple of modern clubhouses — the video room — dissecting a pitcher’s motion to first base and home plate in order to gain the split-second jump that can make a difference.

Another reason for the rapid and pronounced increase in efficiency in the last several years is the inability of the San Diego Padres to keep runners from owning the base paths. Since the beginning of the 2006 season, San Diego has been worse at throwing out baserunners than any other team in the past 50 years. Padres catchers gunned down 26 of 176 would-be thieves in 2006, 14.8%, which was then the lowest percentage since the first year of play-by-play data, 1957. Last year, San Diego broke its own mark, throwing out just 20 of 209 runners, which made it the first team to post a caught-stealing rate of less than 10%. The 2007 Padres also allowed the second-most net steals (stolen bases minus caught stealing) in the modern era — 169, three fewer than the 2001 Red Sox. This year, San Diego is on pace to break that record, too, as it has allowed 90 stolen bases and caught 12, a pace that would lead to a net total of 176 steals over the full season.

How much that inability has actually cost the Padres can be determined using the run expectancy matrix, which breaks down the average number of runs scored by major league teams after reaching any specific base/out situation in a given year — say, when a team has two outs and a runner on first (last year, that led to 0.24 runs). By subtracting the difference between run expectancy in the base/out situation before and after a steal attempt, one can calculate, in the abstract, the number of runs a team scored or lost through its baserunning. For example, with a runner on first and none out, teams averaged 0.93 runs in 2007, compared to 1.19 with a runner on second and none out, so a steal in that situation netted 0.26 extra runs.

By examining the specific context surrounding each base stolen against the Padres last year and each runner they caught, and filtering those situations through the 2007 run expectancy table, one can determine how many runs San Diego cost itself (again, in the abstract) during its historically bad season. This method finds that Padres opponents added around 26 runs through their thefts, which is not far from the +22 derived from plugging in Fox’s average SB/CS values for 2000-07. Ten runs generally equates to one win, so San Diego lost between two and three games, compared to the average team, through its futility.

That’s not a huge total, but it is certainly a significant one, especially given that the Padres lost a one-game playoff for the National League wild card spot last year. The stolen base, then, can indeed be a difference-making weapon, as long as it is utilized efficiently. Lately, the offensive margins where steals had long since been relegated by statistical analysis have been sharpened, to the point where yet another part of the game is close to reaching the harmonious balance that is baseball’s transcendent trademark.

William Burke, Jason Paré, and Dan Fox contributed research to this column. Mr. Peiffer is a writer for Baseball Prospectus. For more state-of-the-art commentary, visit baseballprospectus.com.