The January transfer window is a tricky period for any football club. There is always a temptation to bolster the squad midway through the season, yet there is also a fear that the business might prove to be a disaster.

In the Premier League, there have been some big successes; think Luis Suarez to Liverpool from Ajax in 2011 or Patrice Evra to Manchester United from Monaco back in 2006. Yet it is a time of year when we tend to remember more clearly the men who did not live up to their winter price tags, such as Fernando Torres to Chelsea (£50 million) and Andy Carroll to Liverpool (£35 million). 

Much of the business seems to be done late in the transfer window—and some of the business does turn out to be pointless.

But when a team makes a signing at the eleventh hour, that does not necessarily mean it was a panic buy. And when a projected deal suddenly falls through, it does not mean the buying club has failed to meet its end of the bargain.

January transfer deals are a minefield of complicated negotiations and anxious administrative tasks that leave players guessing and clubs sweating. Daniel Geey is a leading Premier League lawyer and knows more than most about the intricate details that go into completing any transfer.

"Transfers can become a game of bluff and double bluff," he explains. "One transfer can set off a chain reaction. The transfer positions of various clubs—if a club buys or does not buy, waits and negotiates on a particular deal or pulls out of a transfer—can all have consequences for other directly or indirectly linked transfers."

By the time that January transfer window opens for business, clubs will have visions of how they want the month to pan out. Meetings have taken place over which players will be made available for transfers and loans, lists have been drawn up and agreements have been made over which players will be the prime targets to be signed.

The most obvious reasons for a club to recruit halfway through a campaign is to boost promotion or title hopes—or stave off the threat of relegation.

Luke Dowling works as sporting and technical director at West Bromwich Albion and has held similar roles at Portsmouth, Blackburn Rovers, Watford and Nottingham Forest. He has fantastic insight on what goes into a club's planning at this time of year.

"I've had different experiences in January transfer windows while being in different leagues," he told Bleacher Report.

"The main experience in the Championship is actually very similar to the experience in the Premier League, where the end goal at the end of the season is massive—either promotion to the Prem...or staying in it. The January transfer window is the perfect midway marker to improve the team.

"While being in those situations, I've always liked to try and use the January transfer window as much as possible for signing loan players because it's not certain what league you'll be in at the end of the season. The short-term loan contract on the slightly higher wages than you would normally pay seems to be the best way forward.

"The player will return to his parent club at the end of that season, and then your planning can go ahead for whatever league you may be in. The difficult and negative side to this, though, is the percentage of players who fall into that bracket are available for loan because there's a good chance they haven't been playing at their own club.

"This can sometimes put off a manager because of the lack of games. Because of this, the planning can be different to what would go in to signing a player on a permanent contract."

Considering the finances and importance of transfer deals, it is surprising just how many are left until the last minute.

"The January transfer window seems to be busier towards the end for a number of reasons," Dowling explains.

"The amount of games at the beginning of the window I'm sure doesn't help, but because it's such a short period—and by this stage you have a real idea how your season is panning out—managers feel reluctant to let a player go until they have got one in themselves. Naturally, this slows everything down.

"You also normally see a lot of loans in this window so clubs don't have any rush to let them leave. They don't mind telling clubs to wait. If you're offering money down to buy the player then it's different, the deal will be done a lot quicker."

Deadline day has become a major part of the English football calendar, but while TV broadcasters enjoy the drama of it all, clubs are not deliberately waiting for those final days to do deals.

"The arrival of transfer deadline day focuses minds," according to sports lawyer Geey, whose new book Done Deal is released in January. "I can understand how it may seem strange that clubs leave major investment decisions to the last minute—and sometimes, that is the case.

"It should be stressed, however, that even transfers done on deadline day may have been the culmination of weeks or even months of planning, even though—to the outside world—such a deal may appear to be a panic buy."

To get a move off the ground, it is usually a technical director or senior executive who makes an initial call to the target's club. This is the path to making a formal approach—ensuring there are no elements of underhand tactics or tapping up.

It is around this stage that stories often find their way into the media. A call or text will arrive with a journalist from an agent, an intermediary or possibly a staff member who works closely to a highly placed official at one of the clubs.

Once past the initial stage of contact, clubs open negotiations over any terms of a transfer, and this is done through face-to-face meetings, over the phone or, increasingly, over WhatsApp. As one source told B/R: "WhatsApp is the easiest way to contact people quickly and effectively. Conversation can move fast, queries can be resolved quickly and all the information sent is secure."

Deals are complicated, involving release clauses, contract terms, agent fees and the transfer fee itself. There are also other personal issues such as living situations, travel and families to take into account.

Traditionally, scouts spent months compiling notes and files on players before recommending them to a team manager. At some clubs, that model still works, but it is becoming increasingly rare. The game has changed in recent times, and Fulham are a good example of the way data has begun to dictate the way in which transfers begin to happen.

Director of football operations Tony Khan developed a statistical research department at Craven Cottage in 2015, and analytics are now used to identify players who could fit into the team's system.

With the rise of data, some degree of technological or video analysis is applied at almost every top club when searching for talent. Decisions over signings are being made for January—but the manager does not always have the final say.

"Much depends on where the power lies in the club," Geey told Bleacher Report. "In more traditional clubs, the manager continues to be the power base for recruitment decisions, which can mean quicker decisions. Alternatively, some elite clubs have numerous people tasked with first-team recruitment who will feed back into the group to make more collective decisions."

Arsenal are an example of the latter, where Unai Emery has a team of people to assist him. Head of football Raul Sanllehi, head of recruitment Sven Mislintat and managing director Vinai Venkatesham all analyse potential signings before a decision is made.

"Ultimately, much will depend on whether a club needs to generate money by selling one of its core team members—or ideally fringe players—to strengthen particular problem positions or because of a long-term injury," Geey says.

"Sometimes, deals have effectively been agreed in November or December and are announced in the first few days of January. That is when plenty of pre-Christmas planning has already occurred to finalise the negotiation of the transfer."

The next Premier League transfer window opens on January 1 and closes on January 31 (6 p.m. ET/11 p.m. GMT). Dowling admits there is a temptation for stats and data to drive decision making at this time of the year.

"The option of using science over art in this window may come in to play a little more than in the summer, purely because the decisions you're making can be very short-term," he explained to B/R. "Ultimately, you would use both in any transfer window when signing a player on a permanent contract."

But the bottom line is that getting the decisions right in January is crucial. There is no time for signings to slowly find their feet, no time to reassess the squad and no time to rethink the depth of the squad. Between now and May, a team's fate will be decided, and whether those months are successful will have a huge bearing on everyone involved.

"One of the biggest differences between the summer and January transfer windows, I think, is that you see inflated prices in January," Dowling says. "Clubs that are desperate, either trying to stay in the league or going for glory, sometimes pay whatever it takes to get in the player who could make the difference."