How Man City overhauled their squad from a 650,000-strong database

Inside the confines of Manchester City's sophisticated data operation is a fundamental phrase its experts work towards: "What does it take to win?"

In practice, the motto is broken down into three sections: identifying players, evaluating them and assessing how the club could improve them, all with a view to enhancing the statistical probability of City winning the Premier League.

Last season, the club's data department projected they would be there or thereabouts when it came to the title race, but their metrics indicated Arsenal were favourites to be champions. They were accurate.

This time around, City prefer to keep their projections under wraps - but five wins from five Premier League games have prompted predictions from supporters and pundits they will again be the Gunners' closest challengers.

City's devotion to data is at the heart of their efforts to close the gap on Arsenal and BBC Sport has been given unprecedent access to the inner workings of the club's metrics machine as we uncover some of the secrets guiding their work - particularly regarding player recruitment and sales.

Their work is a sign of the times in the Premier League, with clubs across the top flight and beyond increasingly using data for transfers and monitoring their teams' performance.

At City, one of the fundamental aims is to reduce risk of any market transaction, be it a purchase or a sale.

City grade players based on:

The system they play in at their current club and how the manager is asking him and the team to play.

Once those four aspects are observed, City's aim is to understand not just how good the player is but how good he could become at the Etihad.

Since winning the Treble in 2023, City's squad has undergone a vast overhaul using this approach. Only four players from that historic campaign remain.

It is crucial to stress, however, that while data has made an indefinite impact on how City operate in the transfer market, the work of traditional scouts continues to be the primary gauge of whether they decide to move for a player.

"Data plays a role in our decision-making, but it is just one part of the overall picture," City sporting director Hugo Viana told BBC Sport.

"We know data cannot tell us everything about a player. It cannot fully show a person's character, mentality or behaviour.

"That is why we study data insights but focus on the expertise of our scouts and other specialists."

The prominence of data, however, has grown significantly behind the scenes at the Etihad.

Here BBC Sport can take you to the core of some of City's key transfer calls from their extensive three-year squad revamp - including the £116m signing of Elliot Anderson.

From 650,000 players to the No 1 target

The starting point for any new signing is City's database of 650,000 footballers from around the world.

The next step is the brief: what sort of player is the club wanting to recruit.

This usually starts with a position, though that process isn't as simple as it sounds.

City, for example, categorise their full-backs into three types: those who are defensive, those who come inside, and those who play high and wide.

Once the club's data departments have the brief, filters that grade a player's overall ability are applied to whittle down the 650,000-man database to 20-50 names.

Juventus full-back Andrea Cambiaso is one player who has been on City's radar after the data highlighted him, particularly his ability to coming inside to build play in midfield.

That he is comfortable with both feet rated highly on the data, too.

In accordance with the data and the scouting reports it was decided the club would not proceed with their interest in Cambiaso in the previous window, but City's approach is likely to mean he will continue to be monitored.

The longlist of 20-50 names is cross-referenced with the scouting longlist. Generally there is a significant overlap between the players identified by data and the ones already on scouts' radar.

From there, further, more refined metrics are applied to rank and prioritise the longlist.

Scouts will then complete further diligence on the players to reduce the list to a maximum of about six players.

At this point, the club will complete deeper dives into the remaining players, including diligence on their injury record, athletic performance and behavioural habits.

The information is then collated into individual reports called acquisition packs which contain all the key metrics used to inform the decision on a player.