I've read somewhere that in doubles it's easier to hold one's serve, and as a consequence in average there are not as many consecutive breaks as in singles; but no explanation or reference was given. Is it true at all?
As pointed out by others responding to similar questions, there likely aren't statistics like this for tennis available at all. Sports like baseball and basketball have seen an influx of analytics in past years, and although this is also true for tennis, there is still nowhere near the statistical tracking as there is in other sports. Although, if I were to guess as to the validity of the claim that it's easier to hold serve in doubles then I would have to agree based on both prior experience and the reasoning that often times in singles, players are able to hit strong returns to break serves. However, with another player present to try to absorb returns, in my experience watching and playing tennis there are far fewer winners on returns of serve in doubles than in singles. Granted, I have no hard facts to substantiate these claims because tennis has unfortunately neglected to keep up with the advanced analytics that other sports are employing.