Recent research has shown Major League Baseball (MLB) players that bat left-handed and throw right-handed, otherwise known as sinister right-handers, are more likely to have a career batting average (BA) of .299 or higher compared to players with other combinations of batting and throwing handedness. Moreover, possibly owing to early exposure to hockey, Canadian-born MLB players have an increased propensity to be sinister right-handers, however, it has yet to be determined whether this provides a relative offensive performance advantage compared to players born in other countries. Using the largest archival dataset of MLB statistics available, the present study examined the independent influence of batting (i.e., left, right, switch) and throwing (i.e., left, right) handedness combinations and country/region of origin (i.e., Canada, USA, Latin America, Asia, Other) on several indices of offensive performance including BA, slugging percentage (SLG), on-base plus slugging (OPS), on-base plus slugging plus (OPS+), home runs (HR), runs batted in (RBI), strikeouts (SO) and wins above replacement (WAR). Mediation models were also computed to examine whether birthplace influences offensive performance through handedness. Examination of all recorded MLB batters revealed that batting left, regardless of throwing handedness, confers an offensive performance advantage. Since the inception of the MLB, the relative proportion of Canadian-born sinister right-handers is at least two times greater than players from other regions, although being Canadian-born does not provide a direct offensive advantage. Rather, results showed evidence of a significant indirect effect in that being Canadian-born increases the odds of being a sinister right-hander and in turn leads to greater performance across each offensive performance statistic. Collectively, findings provide further support for the hockey influence on batting hypothesis and suggest this effect extends to offensive performance.

Data Availability: A link to each player page can be found at https://www.baseball-reference.com/players/ . The links to each player page were traversed programmatically, and the data from each page was saved from the relevant html <table> tags. This was done in accordance with the site’s terms of use ( https://www.sports-reference.com/termsofuse.html ) and the robot.txt file (which defines the actions permitted by non-human users). Specifically, consecutive page loads were delayed by at least 3 seconds in order to comply with site rules. The authors did not have special access privileges, and interested researchers could access the data using a similar method.

Introduction

Left-handed batting in baseball gives players an advantage over right-handed batters, evidenced by the fact that left-handed batters are more likely to win batting titles than right-handed batters [1]. Several hypotheses have been advanced to explain this finding. For instance, left-handed players are a step closer to first base and the momentum of their swing is orientated in the direction of the run, making it more likely they will beat out close throws [2]. Additional explanations include the novelty or limited experience pitchers have facing left-handers, the increased chance of facing right-handed pitchers (so called “off-handed” matchups), and the possibility to capitalize on shifts in field position. From a neurocognitive perspective, hemispheric lateralization has also been advanced as an explanation [3]. Generally, left-hand dominant individuals show less lateralization than right-hand dominant individuals meaning there is less differentiation in function by hemisphere. This greater flexibility may manifest in advanced skill performance. McLean and Ciurczak [3] first applied this to baseball and were able to demonstrate that dominant left-handed players (players who throw and bat left) were more likely to play in the major leagues and among professional players, were three-times more likely to have career batting averages (BA) over .299. Grondin et al. [2] extended this line of inquiry by examining differences between handedness preference orientations for BA as well as advanced batting performance metrics that reflect power hitting (i.e., slugging percentage [SLG]; home runs [HR]) and plate discipline (i.e., strikeouts [SO], walks). Using a dataset from the inception of Major League Baseball in 1871 to the end of the 1993 season, their results showed dominant left-handed players have higher BAs and more walks than dominant right-handed players, while also batting for a higher SLG and more HRs per at bat than players with all other combinations of throwing and batting handedness preference orientations. However, batting for more power did come at the expense of recording a SO more often in comparison to left-handed batters who throw right-handed. Grondin et al. [2] provided a potential explanation for their findings, in that dominant left-handed batters execute a forehand stroke (as in tennis) which provides biomechanical (i.e., spring effect) and kinematic (i.e., increased peak swing velocity) advantages that facilitate more power as opposed to a less powerful, more reliable backhand stroke that is executed by left-handed batters who throw right-handed.

Recently, Mann, Loffing, and Allen [4] updated and re-analyzed the data originally used by McLean and Ciurczak [3] and found that the biggest advantage in batting was not for dominant left-handed players, but for left-handed batters who throw right-handed, also known as sinister right-handed players. In their analysis, sinister right-handers were more than seven-times more likely to play in the majors relative to the proportion of other combinations of throwing and batting handedness preferences in a representative sample of 538 high school and grammar school students, and more than three and half-times more likely than dominant left-handed batters to have a career BA over .299. The authors suggest that this finding casts doubt upon McLean and Ciurczaks’s [3] proposition that the offensive advantage of dominant left-handed players is attributable to hemispheric laterization. Instead, Mann et al. [4] postulate a biomechanical advantage for sinister right-handers whereby the dominant hand ends up being positioned further from the striking end of the bat, which gives greater leverage and more power in the swing (while also noting it may result in less bat control)[4]. However, the only offensive performance statistic Mann et al. [4] assessed was BA, which would be considered more indicative of bat control than power. Inferring that sinister right-handers have a power advantage directly contradicts findings of Grondin et al. [2], which showed dominant left-handed players hit more HR per at bat and have a higher SLG in comparison to sinister right-handers. Given the difference in findings observed by Mann et al. [4] over 35 years after the original study of McLean and Ciurczak [3], it is also possible that the earlier findings of Grondin et al. [2] will not be supported over twenty-five years later. Findings will lend insights as to whether certain handedness preference orientations provide specific offensive performance advantages for MLB players.

While there is little doubt that there is an advantage to batting left-handed in terms of BA, BA itself is not a particularly sensitive or even accurate measure of offensive performance. Previous research examining advanced offensive performance metrics such as HR and SLG have improved our understanding of potential handedness-based offensive performance advantages [2], however additional advanced offensive statistics will offer further insight regarding this knowledge gap. Notwithstanding the contradicting theories for possible biomechanical advantages of left-handed batters who throw right-[4] and left-handed[2], many of the explanations offered to explain the relative advantage involve more than just the mechanics of the swing. Walks, for example, are just as valuable as hits for getting on base. Situational hitting, that is, adjusting approach at the plate depending on outs and whether or not there are players already on base is also important to evaluate offensive performance. For example, a player that is on base is more likely to advance to the next base on a ball that is hit in play than attempting to steal a base on a SO. Many of the aforementioned explanations, such as capitalizing on right-left matchups in pitching, and adjusting to shifts in field position, suggest reading and reacting to the field are also important. Sinister right-handed batters may be better able to read off-speed and breaking pitches because their dominant eye is closer to the pitcher[5]. This of course assumes they are also right-eye dominant.

Although previous studies have relied on outcomes like lifetime BA [2,4] and SLG [2], these are very limited measures of performance. In the former case, BA is simply the number of times a player records a hit divided by the number of times at the plate. BA does not reflect a players’ ability to draw walks nor does it take into account the type of hit a player makes (e.g. single versus double, triple or homerun). BA is also affected (as are measures of hitting in general) by environmental conditions such as the dimensions of the field (distance from home plate to the outfield wall–right, left and centre field), as well as the altitude of the park. To overcome the limitations of BA, SLG takes into account the productivity of the hitter by giving more weight to extra base hits (e.g., doubles). The equation is: SLG = (((1 * 1B) + (2 * 2B) + (3 * 3B) + (4 * HR))/AB). Where B represents the base, AB is at bats and HR is home runs. As can been seen in the formula, a simple multiplicative factor is included to give relatively more weight to hits that advance the runner further around the bases. However, a major shortcoming of SLG is that this advanced statistic does not account for ‘walks’.

On-base plus slugging (OPS), as the title suggests, adds SLG to on-base percentage (OBP); because OBP includes both hits and walks, OPS provides a more complete accounting of offensive performance. A further adaption, denoted as OPS+, takes into account the influence of different parks on performance. The equation is: OPS+ = 100 * ((OBP / *lgOBP) + (SLG / *lgSLG)– 1). Where *lgOBP and *lgSLG are park-adjusted league OBP and SLG (excluding pitchers hitting performance), respectively. By taking into consideration relative advantages attributable to playing in specific parks, OPS+ is considered an improvement over OPS.

Wins above replacement (WAR) is a summary statistic that is intended to reflect a players’ total contribution to the team. Specifically, the value for WAR represents the number of additional wins the team has achieved above expected wins if the player in question was replaced by a minor leaguer or bench player. Positive values (>0) suggest the player in question contributed more to wins than a replacement player. Although there are some variations in how the components of the formula are calculated, the general form of the equation is: WAR = (Batting Runs + Base Running Runs + Fielding Runs + Positional Adjustment + League Adjustment + Replacement Runs) / (Runs Per Win).

Finally, runs batted-in (RBI) is also an extremely useful offensive statistic, particularly in the current era where hitting for power is dominant. Despite the fact that RBI is widely regarded as more valuable to evaluate player performance than statistics such as BA, research to date on left-handed batting has not examined whether left-handed hitters, including sinister right-handers, outperform other right-handed batters.

Beyond advantages to BA (and possible advantages to other performance statistics), selection of left-handed hitters (both dominant left-handers and sinister right-handers) into the MLB itself is not a random process. Given the advantages of batting left-handed, we might expect for example that left-handed hitters would be selected at a higher rate than right-handed players. Although the proportion or prevalence of left-handed batters in the majors exceeds that which would be expected given the number of left-handed people in the general population [6,7], some countries contribute a higher relative number of left-handed hitters to the pool of players. Cairney and colleagues [5] recently showed that Canadian-born MLB players were far more likely to bat left than players born in the United States, Dominican Republic or South-east Asia (69% compared to 37%, 33% and 30%, respectively). Interestingly, more than 60% of left-handed Canadian-born players active at the time of the study threw right-handed. The explanation for this was linked to ice hockey–a game widely played in Canada. Unlike baseball, hand dominance is much less predictive of bimanual control (i.e., shooting) patterns in hockey [7]. Considered in this context, for those who shoot with their right-hand at the top of the stick, it is a fairly natural transition to place that same hand at the bottom of the baseball bat, resulting in a left-handed swing. According to Cairney et al. [5], coaches and other analysts of the game have speculated that playing hockey first, early in life, produces a higher prevalence of left-handed batters in baseball emanating from this country. Given the advantages to batting left-handed previously noted, Canadian-born left-handed batters are likely to be selected into the MLB at higher rate than players from other countries. At present however, it is not known if Canadian-born baseball players outperform American-born players and those from other countries on the advanced performance statistics identified above.

Given the aforementioned gaps in our knowledge regarding a relative advantage for sinister right-handers, this study used archival data to examine the following research questions. (1) Are there differences in offensive performance across different groups defined by handedness preference with regard to throwing and batting handedness? (2) Do Canadian-born players outperform American-, Latin-American- and Asian-born players as well as players born anywhere else on offensive statistics? (3) Are Canadian born players more likely to bat left-handed and throw right-handed compared to American-, Latin-American-, Asian-born and players born anywhere else? (4) If Canadian-born MLB players have a greater propensity to bat left-handed and throw right-handed, does this provide a relative offensive performance advantage compared to players coming from other places of origin?