That, certainly, is what almost every academic study on the influence of soccer managers has concluded. Some have entered popular discourse: the research in “Soccernomics” that estimated that a manager is responsible for only 8 percent of a team’s results; the work in “The Numbers Game”that placed the figure at around double that.
Some have remained adrift in academia — one, in 2013, found that interim managers tended to have more direct impact on results than permanent ones — but reached the same broad conclusion.
Only the true greats, people like Alex Ferguson and Arsène Wenger, had a tangible, discernible impact. Everyone else was at the mercy of factors not entirely within their control: a club’s financial potency, the quality of player on the books, the strength of their opponents. It is only necessary to glance at Paris St.-Germain to know that, even with a high-caliber manager and a high-quality squad, sometimes the mix is not right; something has to spark, something between chemistry and alchemy, to make things work.
That conclusion, though, is not quite as straightforward as it appears. Eight percent, to use the lowest available estimate, may not sound like a lot, but in the context of elite soccer, in particular, it is a huge and unwieldy variable.
This is a sport, after all, of fine margins: a brief loss of concentration, a slight tactical distinction, a single decision made instinctively by a brilliant player can all decide a game. That the identity of a single staff member can be directly responsible for almost a tenth of the outcome is proof not of a manager’s irrelevance, but of the opposite.