There is a well-entrenched belief in the Overwatch community that grouping up with anything less than a fully organized team is a recipe for disaster. Either you're going to get matched with vastly better players, or you're going to end up in games so lopsided your rating gains and losses will end up being noticeably worse than if you simply played solo. Well, if you subscribe to this sort of thinking, you'll be glad to hear that Blizzard's Scott Mercer has now come out to address exactly these kinds of misconceptions.
"The first and maybe most common misconception I want to correct is the belief that the Competitive Play system decreases your SR gains and increases your SR losses when playing in a group," reads the lengthy developer post. "The simple answer here is that there’s no SR penalty based on your group status. It doesn’t matter if you’re solo, grouped with one other person, or in a full group of six."
"If you are a 2800 SR player grouped with five other 2800 SR players, the SR change after a win or loss is the exact same as if you played the game solo with five other solo 2800 SR players. We also do not artificially inflate the SR of the players in a group when finding matches. There is simply no penalty at all for the purposes of calculating SR and matchmaking."
Your SR gains and losses will still differ from game to game due to a variety of factors, the biggest of which is whether your team is considered the underdog or the dominant one, though all of this applies to solo games as well. Similarly, if you're ranked below Diamond you will your have your rating gains and losses adjusted by your performance in that match, all of which can lead to some fairly wild swings in your SR. Long story short, playing in a group does not influence your SR in any unique way, it only pits you against similar groups in order to offer an adequate challenge for everyone involved.
So worry less about your allies, and worry more about crushing your opponents
"Whenever it [the matchmaking system] wants to make a game, it calculates an expected win percentage for each team based on the SR of all the players. If one of the teams doesn’t have at least a predicted 40% win rate, then we simply don’t create the game," continues the developer post. "Even if you do end up in game where your predicted win rate is close to 40%, it’s important to remember that it also means that your SR will drop less when you lose, and you will gain more SR if you win."
"Among all possible team compositions, the one with the highest win rate is the full team of six players. If we again take into account how often the six-player team composition plays other compositions (and close to 84% are against teams with at least a four-, five-, or six-player group) then they only have an observed win rate of 52.88%. So, there is a very modest advantage to playing in a six-stack. All the other composition possibilities have closer to 50% win rates."
So if you feel like maximizing your chances for victory, and also having a whole bunch of fun in the process, finding a group of players to queue with is an excellent idea. Not only will this give you the option to play whichever role you like, but you will also have five players that you can trust to do their part of the job, which really is the ideal way to play Overwatch. Right now getting those groups up and ready is a bit of a hassle, but soon enough we'll have the "Looking For Group" system to help us out!
Once the LFG system goes live I'll make sure to let you know, but until then I would highly recommend you give Scott Mercer's post a closer look as it's packed with some highly interesting information. Enjoy!