There is a generally accepted rule of thumb about the success each of these boxing styles has against the others. In general, an in-fighter has an advantage over an out-fighter, an out-fighter has an advantage over a brawler, and a brawler has an advantage over an in-fighter; these form a cycle with each style being stronger relative to one, and weaker relative to another, with none dominating, as in rock paper scissors. Naturally, many other factors, such as the skill level and training of the combatants, determine the outcome of a fight, but the widely held belief in this relationship among the styles is embodied in the cliché amongst boxing fans and writers that "styles make fights".
Brawlers tend to overcome swarmers or in-fighters because, in trying to get close to the slugger, the in-fighter will invariably have to walk straight into the guns of the much harder-hitting brawler, so, unless the former has a very good chin and the latter's stamina is poor, the brawler's superior power will carry the day. A famous example of this type of match-up advantage would be George Foreman's knockout victory over Joe Frazier in their original bout "The Sunshine Showdown".
Although in-fighters struggle against heavy sluggers, they typically enjoy more success against out-fighters or boxers. Out-fighters prefer a slower fight, with some distance between themselves and the opponent. The in-fighter tries to close that gap and unleash furious flurries. On the inside, the out-fighter loses a lot of his combat effectiveness, because he cannot throw the hard punches. The in-fighter is generally successful in this case, due to his intensity in advancing on his opponent and his good agility, which makes him difficult to evade. For example, the swarming Joe Frazier, though easily dominated by the slugger George Foreman, was able to create many more problems for the boxer Muhammad Ali in their three fights. Joe Louis, after retirement, admitted that he hated being crowded, and that swarmers like untied/undefeated champ Rocky Marciano would have caused him style problems even in his prime.
The boxer or out-fighter tends to be most successful against a brawler, whose slow speed (both hand and foot) and poor technique makes him an easy target to hit for the faster out-fighter. The out-fighter's main concern is to stay alert, as the brawler only needs to land one good punch to finish the fight. If the out-fighter can avoid those power punches, he can often wear the brawler down with fast jabs, tiring him out. If he is successful enough, he may even apply extra pressure in the later rounds in an attempt to achieve a knockout. Most classic boxers, such as Muhammad Ali, enjoyed their best successes against sluggers.
An example of a style matchup was the historical fight of Julio César Chávez, a swarmer or in-fighter, against Meldrick Taylor, the boxer or out-fighter (see Julio César Chávez vs. Meldrick Taylor). The match was nicknamed "Thunder Meets Lightning" as an allusion to punching power of Chávez and blinding speed of Taylor. Chávez was the epitome of the "Mexican" style of boxing. Taylor's hand and foot speed and boxing abilities gave him the early advantage, allowing him to begin building a large lead on points. Chávez remained relentless in his pursuit of Taylor and due to his greater punching power Chávez slowly punished Taylor. Coming into the later rounds, Taylor was bleeding from the mouth, his entire face was swollen, the bones around his eye socket had been broken, he had swallowed a considerable amount of his own blood, and as he grew tired, Taylor was increasingly forced into exchanging blows with Chávez, which only gave Chávez a greater chance to cause damage. While there was little doubt that Taylor had solidly won the first three quarters of the fight, the question at hand was whether he would survive the final quarter. Going into the final round, Taylor held a secure lead on the scorecards of two of the three judges. Chávez would have to knock Taylor out to claim a victory, whereas Taylor merely needed to stay away from the Mexican legend. However, Taylor did not stay away, but continued to trade blows with Chávez. As he did so, Taylor showed signs of extreme exhaustion, and every tick of the clock brought Taylor closer to victory unless Chávez could knock him out. With about a minute left in the round, Chávez hit Taylor squarely with several hard punches and stayed on the attack, continuing to hit Taylor with well-placed shots. Finally, with about 25 seconds to go, Chávez landed a hard right hand that caused Taylor to stagger forward towards a corner, forcing Chávez back ahead of him. Suddenly Chávez stepped around Taylor, positioning him so that Taylor was trapped in the corner, with no way to escape from Chávez' desperate final flurry. Chávez then nailed Taylor with a tremendous right hand that dropped the younger man. By using the ring ropes to pull himself up, Taylor managed to return to his feet and was given the mandatory 8-count. Referee Richard Steele asked Taylor twice if he was able to continue fighting, but Taylor failed to answer. Steele then concluded that Taylor was unfit to continue and signaled that he was ending the fight, resulting in a TKO victory for Chávez with only two seconds to go in the bout.