Sports analytics, data collection and analysis, when coupled with mathematical and statistical models of data interpreting, can contribute to an improved performance development among both individual players and teams during basketball games (
26). Therefore, in-game statistics has become the subject of interest of both basketball coaches and scientific researchers (
27); most of the research papers quoted in the present work have dealt with basketball games using quantitative analysis as the basis for describing and understanding individual and team performance during basketball matches (
28). Data collected and analyzed accordingly, may be used in different ways - but in recent years they have mostly been used to discriminate between the winning and losing teams (
29). Following the suit, the present study aimed to make an analysis relating to which variables, during 29th FIBA Asia Cup, discriminated between the winning and losing teams.
This continental championship was held according to a specific combined tournament format and did not have issues as some researchers had in their works, like home-court advantage or in-form and out-of-form team performances during season long competitions, or as some authors described this phenomenon: “Discriminate between season-long successful and unsuccessful basketball teams” (
27) in season-long national championships. Due to the relatively small number of games played during this continental championship, we didn’t make different game subgroups as the differences between the winning and losing teams, in that respect, were not evident in terms of the standard indicators of basketball efficiency. Here we have followed cluster analysis guidelines of Jaime Sampaio and Manuel Janeira, who defined three types of basketball matches for subsequent analysis based on final score differential: close games (games with undecided results up until the very last seconds of the game played), balanced games (games with relatively low final score differential), and unbalanced games (games with relatively high final score differential) (
30), because the games played at this continental championship tended to discriminate following the same outline. Future research should focus on the differences between winning/losing teams in a round robin system relative to differences between winning/losing teams in single-elimination system (final stage of championship), as was done by some authors who compared regular season matches to play-off matches (
30).
In both observed models, variables included in the first step of iteration were the variables related to field goals: In the first model, the included variable was field goals made (R
2 = 0.76, F(1, 38) = 127.24, P < 0.00), explaining 76% of difference between the winning and the losing team at 2017 FIBA Asia Cup, while the second model had the variable of percentage field goals (R
2 = 0.49, F(1, 38) = 38.27, P < 0.00) explaining 49% of the difference. To have the variables related to field goals made and field goals attempted as the ones which explain most of the observed phenomenon, is consistent with logic in which the dependent variable of total points scored discriminates the winning from the losing team. Many other researches have come to the same conclusion, i.e. percentage of field goals is the variable with the most significant influence on the discrimination between the winning and losing team (
25,
27,
31-
35). After all, shooting is one of the most important skills in basketball players. Even if a player has an improved arsenal of other basketball skills, including passing, dribbling, rebounding and defense, which may help him to have high field goals percentage, he will still need to have sufficient shooting skills to score points (
23,
36), or as Bill Sharman, one of the four people who was inducted into Naismith Memorial Basketball Hall of Fame both as player and coach, put it: “He wins who scores more points than his opponents in basketball, and shooting is the backbone of the game” (
37).
It comes as pretty much coherent with everything said so far that out of eight variables included in this work, six of them (75%) relate to the shooting efficiency, 100% in the first model and 60% in the second model, respectively. Alongside with the variables filed goals made and percentage field goals, free throws made and 3 points made were found significant in the first model (absolute values), and the same for the second model (relative values) - percentage 3 points and percentage free throws. The same findings can be retrieved from many other works - free throws and their efficiency (
28,
30,
38-
40), and efficiency of 3 point shots (
33,
41,
42).
Some previous works (analyzing data from 13th, 14th and 15th World Championship), which applied the same researching methodology as the present study, found the shot-related variables to be dominant in both models (
25). The models developed for those championships had nine included variables which were significant in discriminating the winning from the losing team - six out of nine relate to the shooting parameters (66.67%) at the World Championship in Greece, five out of nine (55.56%) at the World Championship in USA, and seven out of nine (77.78%) are shooting variables which were found significant at the World Championship in Japan. It is noteworthy that all the three abovementioned basketball championship reported ΔM2 (2 points made) as the dominant variable with a significant influence on the final score of the game, the same was observed in other researches as well (
30,
31,
33,
41,
43), whereas such an outcome was not included as a separate variable; although it was indirectly included as the part of variable field goals made and percentage field goals (presented in this study as sum of ΔM2 + ΔM3). The Asian continental championships held in 2011, 2013 and 2015 recorded a high correlation between 2 points made and the winning teams but only in unbalanced games (
24). What might be the underlying cause for this? Many things could account for it: Conceptual and strategic frameworks that participating teams chose to follow, tactical shifts towards certain playing styles, number of players capable of making 3 point shots, tall players capable of taking behind the three-point line shots, etc. Note also that some authors found that in games with winning margin less than 10 points, the winning teams had better 2 point shot percentage, whereas in games with margins of 10+ points, the most significant influence on the final score was recorded in defensive rebounds and assist passes (
43). At FIBA Asia Cup 2017, 62.50% of games had final score with 10+ points difference, which points, on the one hand, to uneven balance in quality of the participating teams and, on the other hand, it also indicates that the lack of ΔM2 can be explained by the apparent difference in the quality of the participating national teams.
The similar work whose focus was on the two models from EuroBasket 2011 included thirteen variables, out of which nine, or 75%, were shooting efficiency indicators (
44). Therefore, one of the conclusions here is that if teams were to win a basketball game, they should aim at creating plenty of shooting opportunities for their players - a notion observed by other researchers as well (
45).
Other studies of the influence of certain game elements on situational efficiency have also found that shooting efficiency and defensive rebounding significantly influence dominant variables in terms of determining the final score of the game (
27,
35,
38). Gomez at al. found defensive rebounding as a separate factor which made difference between winning and losing (
31), Garcia et al. highlighted the efficiency of 2-point and 3-point shooting with defensive rebounding and assist passes, during the regular season matches, whereas only defensive rebounding had a discriminating influence on the winning/losing team difference in play-offs (
43), and de Carvalho et al. found that the game winning was dependent on defensive rebounding, assists, turnovers and 2-point and 3-point shooting efficiency (
42). Bartholomew and Collier claim that: “... basketball defensive players and teams are evaluated on traditional basketball metrics such as blocked shots, defensive rebounds, steals, forced turnovers, fouls, and the opponent’s total points and field goal shooting percentage” (
46,
47), whereas Trninic et al. assert that: “...defensive rebounds to be not only an indicator of the closing defensive actions, but also as an indicator of overall defensive success; since it follows the unsuccessful opponent’s shot which is, most often, a consequence of the organized pressure defense well performed” (
48). Basketball teams with efficient defensive rebounding get more opportunities for shooting, thus creating more scoring chances and potentially win matches (
30). Here we have to clarify that it is not just the number of defensive rebounds that can be taken as a reliable indicator, but the efficiency of defensive rebounding as such - something that was pointed out as early as in 1982 by one of the greatest coaches of all times, Dean Smith, in his book titled “Basketball, multiple offense and defense” (
49). His research also showed that the winning teams had on average more defensive rebounds, M = 28.20 (0.74), when compared with the losing teams, M = 22.60 (0.86), but also they had more rebounding opportunities on average (3.65). It is only when we take the relative indicators of defensive rebounding that we get a complete picture with respect to the winning teams and their defensive rebounding, i.e. the winning teams managed to get possession of 70% of the shots missed by their opponents, M = 69.64 (1.28), whereas the losing teams got 60% of the missed shots from their opponents, M = 60.65 (1.45).
Madarame found the link between defensive rebounds and winning the matches in both balanced and unbalanced games at three Asian Basketball Championships preceding the 2017 FIBA Asia Cup (
24). The situational efficiency variable of defensive rebounding was therefore, alongside with assist passes, found in all the matches played at the championships.
Kubatko et al. proposed, based on their research findings, the inclusion of the four factors into offensive and defensive efficiency analysis, by the following order: Field goal efficiency, offensive rebound percentage, steals and free throws (
50). The importance of turnovers relative to the winning/losing outcome of the game was stressed by many researchers (
41,
42). For example, a study conducted by Nakic found correlation between the losing teams and personal fouls, turnovers, and missed 2- and 3-point shots (
51). This segment of the game was also examined by Fylaktakidou et al., and they found that the underlying reasons for turnovers were the following: passing errors 40.00%, fault ball handling 23.90% and travelling 23.60% (
52). Our research found, in the second model, that ΔTO had a significant influence on the final score and that, together with ΔFG%, explained 66% of the research phenomenon (R
2 = 0.76, F(3, 36) = 62.54, P < 0.00). This is in line with previous research findings about the defensive rebounding. The winning teams were found to have less turnovers, M = 13.88 (0.53), in comparison to the losing teams, M = 16.50 (0.74). The losing teams had even 1.75 attacks more than the winning teams, or in other terms, they had more of a chance to make more turnovers. It is only with the absolute indicators that we get the clear picture about the whole issue, i.e. relative to the number of offenses, the losing teams made 3.4% turnovers more than the winning teams.
The limitations of this study are primarily concerned with the nature of the study as with regards to the validity and reliability of research findings. For instance, Hughes et al. analyzed different studies (n = 72) from the field of notational analysis and found that almost 70% of authors conducted no examination about the reliability of performance and efficiency indicators (
53). Likewise, we should bear in mind that the study data are often provided by data collectors who may not have ample experience in the field, resulting in serious consequences on the reliability of the entire study (
54). On the other hand, even coaches are known to be able to observe only around 30% of the events taking place in the course of a basketball match (
55). Therefore, we need a reliable and objective set of tools for evaluation of individual and team performances - one example could be the performance analysis (
56), a notational approach, which requires an on-going development in terms of its methodological compatibility and overall reliability.
Ibanez et al. pointed out that there are too many studies focusing on game variables differentiating between the winning and losing team but only during a season or two, or during international competitions at best, whereas seldom is the case when researchers examine a set of different basketball seasons for this purpose (
27), not to mention a relatively small number of studies examining two or more international competitions (continental championships or cups). Any further research should go in that particular direction (examination of data from consecutive Asian Championships/Cups), and it should be carried out in the similar format with the inclusion of additional game parameters.
5.1. Conclusions
The present study applied the gradual regression models on the eight variables that were found to have the most significant influence on the final score, i.e. those that made most of the difference between the winning and losing teams at 2017 FIBA Asia Cup. Most of the included variables were related to indicators of field goals made, free throws and percentage of points made. Also, the included variables were those relating to defensive rebounding and turnovers. The results obtained in this study are in accordance with many other studies - overall shooting efficiency, particularly field goal efficiency, and defensive rebounds were found to be the main parameters of the situational efficiency with significant influence on the final score in basketball. The obtained results may have a practical value in terms of providing guidelines for basketball coaches in their efforts to maximize the benefits during preparation of their teams for the competitions and regular seasons.