The expectations of football fans at the start of the season can be broadly split into two camps. Supporters of around half a dozen teams can look forward to a season where the anxiety revolves around title aspirations and UCL or Europa league qualification. Some even organise a flypast to celebrate the latter. The remainder of have-nots can't wait to get to the magical 40 points quick enough and reach the generally accepted threshold for continued membership of the top flight.
The 40 point target usually leaves quite a bit of room for error, the mid to high thirties has generally been sufficient to finish outside the bottom three throughout the history of the 38 game Premiership. Only West Ham (42 points) in 2002/03 have been relegated with more than 40 points, although Everton needed a superior goal difference to go with their two score points to survive in 1997/98 and Sunderland found 40 points insufficient a year earlier.
Each of these seasons were atypical of the current EPL. Everton's near miss-hap and Sunderland's demise came in a period when fewer than 80 points were needed to win the title, so "extra" points filtered down the league and West Ham suffered partly through the generous nature of the other two relegated sides, WBA (26 points) and Sunderland (19 points).
This demonstrates that while historical precedence can give a baseline figure, factors unique to particular seasons also wield some influence.
If the likes of Derby, Coventry and Sheffield Wednesday hadn't embarked on unlikely goal scoring sprees against Bolton in 1997/98, Everton would have suffered relegation on goal difference instead of clinging to their top flight status.
And if WHU had swapped an impressive 3-2 win away at Chelsea for a much more valuable win at lowly Bolton in 2002/03 instead of the narrow 1-0 defeat they actually suffered, the Hammers 42 points would have been sufficient and Bolton would have dropped into the Championship with 41 points.
Therefore, goal difference, an intertwined fixture list (14 of the remaining matches are head to heads between teams currently occupying one of the bottom nine places) and the proximity of the relegation candidates to each other, each add layers of uncertainty to the survival target of the threatened sides. And these effects become more apparent as the season winds to an end.
The case of Crystal Palace illustrates some of these factors. Their run in is tough and two matches away at both Cardiff and Fulham present them with one of their best opportunities to pick up points in their remaining matches. If they do take points from these games they will deny one or more of their pursuers the chance to take maximum points. Additionally they have a superior goal difference and this is likely to be the case after 38 games.
Palace's goal difference under Pulis' 20 matches in charge is -4, compared to -15 in the first 11 matches before his arrival. Even if they only limp to 34 points by May, simulations indicate that they will still have just over a 50% chance of beating the drop.
34 points is not only at the lower end of the points estimate for Palace by the end of the season, (their most likely total is 38 points), but it also gives them a better than even money shot at staying up.
But what about their relegation rivals, Sunderland, currently lying in 19th place with 25 points from 30 games. Palace are an obvious target for Sunderland, but their fixture lists don't cross again this season, although their goal differences are very similar. However, they do play WBA whom are also struggling at the foot of the table, but the Baggies have an easier run in than Palace, as well as a superior goal difference. To complicate matters further, Cardiff also visit the Stadium of Light at the end of April.
If Sunderland reach 34 points, (an over-achievement on current evidence), how will all these intertwined factors play out in terms of their survival chances?
The easiest way to unravel this is to again simulate actual seasons and see how often 34 points sees Sunderland safe compared to others marooned at the foot of the table.
The table above appears to indicate that rather than a single survival line at this late stage of the season, each team has its own individual target. The chances of enough teams emerging from the bottom of the pack to relegate Palace if they end the campaign with just 34 points is around 53%.
In contrast, the likelihood that Sunderland will find enough sides to catch should they gain 34 points in a multitude of different iterations of the remaining 64 matches is only 30%. Cardiff, especially with their poor goal difference, need a near superhuman 36 points before they are more likely than not to remain in the top flight, as most of the birds will have flown to a slightly higher perch.
The playing field is level in August, but by May the really struggling teams appear to be required to clear a slightly higher bar just to give themselves a similar shot at surviving the drop.
*although Fulham aren't on the (slightly cluttered) plot, they are of course included in the simulations. Their potential fate is slightly worse than that projected for Cardiff.