From being one of the top-ranked Test sides from 2010 to 2013 - a period during which they won 17 out of their 26 home Tests, while losing only three - England have slipped to No. 5 in the latest ICC Test rankings.

While England's ordinary away record in the recent past is understandable - a trend that holds good for most sides these days - their recent defeats in home Tests have raised a few eyebrows.

Since the beginning of the 2014 season - when they lost 0-1 to Sri Lanka in a two-Test series - England have lost 10 out of 30 home Tests. Four of those losses have come in the last 10 games, indicating a steady decline. ESPNcricinfo looks at the numbers and key factors that have contributed to this slide:

Middle-order's exposure to the new ball

It helps if the openers can see off the new ball in English conditions. This makes it easier for the batsmen to follow, and gives teams a chance of posting competitive totals. Numbers back this theory.

Since 2014, the average total when openers have failed to play out at least the first 15 overs is 290.5. This average increases to 437.5 when the openers have successfully managed to grind this period through.

Since 2014, teams scoring at least 350 in the first innings in England have not lost 82.7% of the times. Teams are a lot more likely to get there if their openers give them a solid start. Teams have managed to score 350-plus only on 23 out of the 83 occasions where the openers haven't failed to play out the first 15 overs. But when the openers have lasted the first 15, teams have posted 350 plus in 13 out of 21 instances.

Impact of opening stands in England ESPNcricinfo Ltd

This is precisely an area that has seen a worrying trend for England. In the last 10 Tests, their opening pair have failed to bat out the first 15 overs in 15 out of 18 innings. In 11 of these innings, they've failed to post 350 or more. Each of their four losses in the corresponding period at home have come when they have failed to post 350-plus in the first innings.

Cook's addition to England's opening concerns

England's opening problems have stretched for far too long now, since Andrew Strauss' retirement in 2012. They've tried 12 different opening combinations with Cook.

While his partners have averaged just 18.5, Cook himself has failed to convert starts, but for a 243 against West Indies at Edgbaston. Excluding that knock, he's made 488 runs in 17 innings at 28.71.

Cook & other England openers (last-10 home Tests) Batsman Inns Runs Ave 100s/50s Alastair Cook 18 731 40.61 1/3 Cook excluding 243 v WI 17 488 28.71 0/3 Other openers 18 307 18.05 0/0

Cook has been dismissed every 86 deliveries in his last 10 home Tests, 13 fewer than his average since 2014. Exclude the Edgbaston epic and this average further dips to just 68 - his dismissals have come 31 deliveries earlier than his average since 2014.

Alastair Cook's balls-per-dismissal numbers ESPNcricinfo Ltd

Root's inability to convert

No one has crossed the fifty-run mark in Tests as often as Joe Root since his debut in 2012. Many of these innings have come in recent times with England having lost early wickets. Root has rescued his team from tricky situations time and again by holding one end up. What he has often failed to do though, is convert these into big scores.

Root hasn't had the same consistency as a Younis Khan when it came to making his starts count. However, until the end of 2015, he wasn't at the bottom of the pile when it came to converting fifties into hundreds. Out of the 21 instances when he made a fifty, he managed eight hundred plus scores. His conversion rate of 38% ranked was joint-15th among 23 batsmen who had ten or more such innings.

But that conversion rate has come down alarmingly since the beginning of 2016. Root has been seemingly in excellent touch, getting to a fifty 28 times in 60 innings since then, which is nearly every other innings.

However, out of these 28 innings, Root has managed to get to three figures only five times for a conversion rate of 19.23% (excluding unbeaten fifties) - almost half of his not-so-high standards from earlier. Since 2016, his conversion rate ranks a poor 18th among 19 batsmen in this period.

Joe Root's conversion rates in Tests ESPNcricinfo Ltd

Lack of control from spin

After Graeme Swann's retirement, England have turned to Moeen Ali to fill the former's shoes as their lead spinner. While Moeen has done reasonably well in patches - he did well in the 2014 series against India and against South Africa last year - he has failed to provide England with the control that Swann afforded them.

From the 2010 home season to 2013, Swann bowled 10 or more overs in a Test innings 34 times, and went for runs at an economy of 3.5 or worse only five times. In comparison, Moeen has had 22 bowling innings when he has gone for 3.5 runs an over or more.

Swann v Moeen comparison ESPNcricinfo Ltd

Moeen has not had a single spell when he has bowled at least 10 overs at less than 2.5 runs an over. In contrast, Swann managed it eight times in home matches from the period 2010 to 2013.

Moeen has conceded nearly a run more than what Swann did in home Tests from 2010 to 2013, and is clearly not the strike-bowler Swann was either: Moeen has taken just three five-fors in 28 matches; Swann had seven in 25.

Graeme Swann v Moeen Ali (home Tests) Bowler Period Mat Wkts Ave Econ 5w/10w Graeme Swann 2010-2013 25 99 28.15 2.99 7/1 Moeen Ali 2014-present 28 82 33.47 3.85 3/1

Musical chairs for the third seamer's spot

Much like their struggle to find an opening partner for Cook, England have struggled to find a steady third seamer for a while. However, unlike with their openers, England's troubles in finding their third seamer have not been solely due to non-performance. Many of the bowlers, including Chris Woakes, Steven Finn, Jake Ball, Craig Overton, Mark Wood and Toby Roland-Jones, have been sidelined with injuries with annoying regularity.

In Tests since 2014, England have tried eight bowlers for the third-seamer's slot and none of them have been able to play more than four Test matches successively. The third seamer's spot has seen 22 changes since 2014. Out of the 44 matches when James Anderson and Stuart Broad both have been in the team, Chris Woakes has managed to play 16 Tests, the most among the eight bowlers that have been tried.

England's third seamer spot ESPNcricinfo Ltd

The lack of continuity is reflected in their ordinary numbers as well. Since 2014, the eight bowlers - including Liam Plunkett and Chris Jordan in addition to those mentioned above - have collectively taken 159 wickets in 54 Tests at an average of 35.23. Inferior numbers in comparison to Anderson and Broad, who have taken 197 wickets at 20.62 and 154 wickets at 28.26, respectively, in these Tests.

England fielders' butter fingers

England haven't been at their best at holding on to the chances created by their bowlers in the recent past. According to ESPNcricinfo's ball-by-ball commentary, England have spilled at least 71 catches in 25 Tests in the last-two years. That's nearly three catches per match. In comparison Australia and South Africa - two of the best fielding teams in recent times - have dropped 47 catches in 23 matches and 57 catches in 27 Tests, respectively, in the same period.

Assuming that the sum of drops and catches make up the total chances created by the bowlers for a team, England's fielders haven't converted 22.7% of the chances created by their bowlers. The corresponding figure for Australia and South Africa is 15.3% and 15.6%, respectively.

What is perhaps of greater for concern for England, especially when playing at home, is that more than 50% of their drops (36 out of 71) have happened in the slip cordon and gully.