Dundee United soccer manager Micky Mellon (pictured above) has written a book with high school headteacher Phil Denton on succeeding in management – The First 100 Days. The focus is on soccer, but also more generally via Phil’s high school, and in particular on the first 100 days.

It’s a great read, packed full of management wisdom applied in the case of both a range of football clubs, with plenty of input from Ole Gunnar Solskjaer, the current Manchester United manager amongst others, and a more conventional setting of a high school.

Chapter 2 in particular talks about the importance of getting off to a good start – winning that first game. It’s clear that many great managerial reigns have begun with a rousing win – perhaps none more so than Joe Royle at Everton, starting with a 2-0 win over arch rivals Liverpool. Royle’s time at Everton was surely a success, winning them their only major trophy since 1987 when winning the FA Cup in 1995.

And it certainly lasted longer than 100 days. Not all managers get that far. Denton and Mellon’s book is all about those 100 days, and the premise clearly is surviving them. Prior to the 1970s, almost all managers survived their first 100 days. Now, as shown below in a plot which records the proportion of managers that survive 100 days, it’s closer to 75%.

That is, three out of four managers make 100 days in their job. One in four fail and are sacked or resign in that first 100 days.

An interesting empirical question given the data exists is the extent to which that first match matters. Just how essential is that first win? In the entire history of English soccer, 85% of managers have made 100 days. If the manager wins that first game, he is 88% likely to still be in the job after 100 days based on raw numbers, whereas if he loses, he is only 82% likely to be in his job 100 days later.

But what about particular managers? Denton and Mellon talk a lot about Sam Allardyce, who has a long track record of turning clubs around – huge amounts of experience. Is he different to a rookie manager starting out? A manager starting at Everton or Manchester United surely has a different likelihood of sticking it 100 days than a manager at Stevenage or Crawley Town? A manager starting his 100 days in 2021 has a much lower chance (about 75%) than one starting the job in 1955 (closer to 100%).

Can we control for all of this? Well, we can give it a go. When we do, controlling for the kind of club, the manager themselves, and the season, we find that winning the first match increases the likelihood of lasting 100 days by about 2.5 percentage points. That is, a manager might be 75% to still be there in 100 days, but if he masterminds a win in his first match, that percentage increases to 77.5%. If they lose, it falls 2.5 percentage points to 73.5%.

So it’s not a huge effect. And it isn’t statistically significant. This doesn’t mean that Mellon and Denton are wrong to focus on that first win. It can clearly be transformative. Rather, it suggests that everything else that’s in their book is what really matters – what explains most of the likelihood a manager lasts 100 days. Building the relationships, thinking about the “why” questions, having the difficult conversations, getting people on your side, keeping them on your side, processing, reflecting, all the things that a manager needs to do in any organisation.