Next Liverpool manager: Ranking Ruben Amorim, Thomas Tuchel, Roberto de Zerbi and more

A version of this article was first published on 23 February

Liverpool still need to find a replacement for Jurgen Klopp after bookmakers' and fans' favourite Xabi Alonso announced he was staying at Bayer Leverkusen.

The former Spain midfielder, who looks set to lead Leverkusen to the Bundesliga title, was a reported target for Liverpool and Bayern Munich - two of the clubs he played for.

Liverpool need a new manager for the first time since October 2015, after Klopp revealed he would be stepping down at the end of the season.

Klopp has won the Champions League, Premier League, FA Cup, two League Cups, Club World Cup and Uefa Super Cup during his Anfield tenure - and Liverpool are still in the hunt to win the Europa League and top flight this campaign.

Carteret Analytics - which provides detailed manager assessments to Premier League, EFL, Bundesliga and MLS clubs - has assessed a series of possible candidates, as well as Klopp, to see who would do the best job.

When the analysis was first done, Alonso - who was still in the running - was only ranked fifth out of the six potential candidates.

The company says: "Not only has Klopp achieved significant success over the past six seasons in terms of results, his individual metrics demonstrate an exceptionally high level of 'football intelligence'.

"For example, his strategic intelligence rating is very high. His tactical command rating is even better."

If you are wondering what strategic intelligence and tactical command are, read on. For in working out the person to replace Klopp, it's all about the metrics.

We list the candidates in order of their suitability according to Carteret's analysis, based on a number of key metrics to give an objective sense of the strengths and weaknesses for each head coach.

(The findings are based on actual results that have been achieved over the past six seasons, incrementally weighted towards the most recent seasons, and relative to the strength of the league in which those results have been achieved.)

How are the managers rated? The metrics defined

Objective achievement rating: A measure of overall ability based on the premise that the primary objective is to win football matches - rather than, for example, long-term player development or balancing of club finances.

Overall rating (weighted metrics): An overall rating score, based on the actual achievements of the head coach over the past six seasons, but weighted according to their individual performance - so are they overachieving or underachieving in their job?

Strategic intelligence rating: The manager's ability to prepare and set his team, and analyse the opposition, to maximise the chances of winning the next match.

Tactical command rating: A measure of the manager's ability to transform a match (during the match), and, in particular, to develop a winning position for the team from various match scenarios.

Attacking coefficient/success-adjusted attacking coefficient: A measure of the manager's propensity to play an attacking style of football - and the relative impact of the manager's attacking coefficient on the success of the team. Does the style bring wins?

Team shot conversion rating/opposition shot conversion rating: A key metric that highlights a team's ability to increase the probability of winning matches. Are they taking the chances they create?

Shot creation ratio: How many chances a manager's team creates.

Possession: How much of the ball a team has.

Sporting Lisbon manager Ruben Amorim has won the Primeira Liga title in 2021 as well as two Taca da Liga trophies with the club

Ruben Amorim (Sporting Lisbon) - even better than the real thing?

Portuguese manager Amorim, 39, has emerged as Carteret's surprise ideal candidate to take over at Anfield.

His stock has risen after guiding Sporting to their first top-flight title in 19 years in 2021 and Carteret says all the analytics point to him "becoming a very compelling option as the next Liverpool manager".

Those findings make allowances for the fact Amorim's experience is in a less competitive league, but say his strategic intelligence rating, his tactical command rating, success-adjusted attacking coefficient and shot creation ratio are all even higher than Klopp's, with an equivalent shot conversion rating and overall levels of possession.

Julian Nagelsmann (Germany interim manager) - hype, headaches and a patient 'genius'

The former Bayern Munich boss, 36, took over as Germany manager in September but his contract only runs until July 2024 and he would be available after this summer's European Championship.

He previously shared the same agent as Klopp - Marc Kosicke - and was described by the current Liverpool manager as a "young horse" and a "big, big coaching talent", with Carteret giving him the highest strategic intelligence rating of anyone.

Its findings suggest the German has a defensive approach but one which he makes work for his teams, with a very methodical, patient and probing style of play.

Carteret does point out, though, that his interpersonal skills would need to be researched more fully and that his style of play could become a problem if not winning matches.

Thomas Tuchel (Bayern Munich boss) - defensive in every sense

With the exception of Klopp, Carteret found Bayern boss Tuchel - who is leaving his post this summer - is "the best of this group of head coaches in demonstrating the ability to win matches at the requisite level" in recent years.

Tuchel rates well in setting up his teams to maximise the probability of winning the next match, but Carteret finds he begins to fall well short of Klopp in his ability to transform matches.

The former Chelsea boss, who led Bayern to the title last season, was also found to have "a very similar defensive style of play as Nagelsmann, and that could prove to be a challenge for Liverpool supporters and for maximising the attacking coefficients of the current Liverpool players".

Ange Postecoglou (Tottenham) - attack, attack, attack... or is it?

Carteret found some strong similarities between Postecoglou, 58, and Klopp - with strategic intelligence, tactical command, and shot creation ratio broadly equivalent (although all lower than Klopp), as is overall possession.

It finds, though, the subjective perception that he has a very attacking style of play was not borne out by objective analysis. Postecoglou's attacking coefficient (23.18) - 16% lower than Klopp.

Carteret says this indicates a less progressive style of play - and adds that the defensive elements of that style were also less successful.

"When you consider some of the fundamental metrics that indicate, empirically, transferable success traits, he becomes a serious consideration as the next Liverpool manager. However, there are probably even better candidates," Carteret said.

Roberto de Zerbi (Brighton) - a passionate style?

With the exception of his brief stint at Shakhtar Donetsk - when he won two-thirds of his matches and led them to the Ukrainian Super Cup - De Zerbi's teams have been firmly mid-table, Carteret says.

There is not a lot, therefore, in an assessment of his results that suggests he can win the Premier League with Liverpool.

Carteret also found none of his metrics are a match for Klopp. Indeed he is significantly lower across the board - strategic intelligence, tactical command, attacking coefficient and shot conversion.

They say: "De Zerbi has certainly created headlines in the UK (as have Brighton as a club generally), but a fully objective analysis of his performance levels (rather than a subjective view of his approach and personality) illustrates that he falls short significantly (in every key metric) from what is required for the next Liverpool manager."