For some years now certain individuals – for the sake of argument let's call them "people" – have been coming up to me and saying: "How does someone like Avram Grant keep getting top‑level coaching jobs?"

It was easy to see why these questers are seeking enlightenment; even to the point of believing I can deliver it. Grant is by all accounts a thoroughly decent chap, but to me his career always calls to mind the summary of the Boro manager Bryan Robson during his final months at the Riverside Stadium that was offered up one drizzle-tormented Saturday afternoon by a burly bloke from North Ormesby with the timbre of a fractured exhaust: "If he fell in a barrel of tits, he'd come out sucking his thumb."

How then had a man so singularly drained of hap as the 57-year-old Israeli ended up controlling Chelsea, Portsmouth and West Ham United? I had no idea. Then last week a friend of mine who is a research scientist started explaining to me the nature of clinical trials – you have the product that is under scrutiny, a positive control and a negative control or placebo.

As soon as I heard this I surmised what was going on: somebody – I'm not certain who they are, but surely the white-coated boffins of the Sir Norman Chester Institute will have something to do with it – have been carrying out a clinical trial on football managers, and Avram Grant is the distilled water. Yes, he looks like a genuine football manager, he sounds like a genuine football manager, but any effect he has, whether it is positive or negative, on the guinea pigs – for the sake of argument let's call them "footballers" – who are given him in the trial is purely psychological.

First off the researchers used Grant to test the effectiveness of other managers in the Big Four. The positive control in this experiment is clearly Sir Alex Ferguson. We know for certain that Sir Alex works – 12 Premiership titles are proof enough of that – even if he can have unfortunate side-effects (the tearing out of hair, raised blood pressure, the urge to yell: "Stop blaming the refs for everything, you puce hoodlum" at the telly).

The trial was conducted over the course of a season and – Oh dear, the inert substance did rather well – second place in the Premier League, Champions League runners-up and beaten finalists in the League Cup. In fact only the positive control was more effective, leading – or at least so I would imagine, for as yet no findings have been published – the researchers to conclude that when it comes to running a top English club a sugar-coated pill is more effective than either Arsène Wenger or Rafa Benítez.

In the next set of trials the placebo/Grant was used to test managers at the lower end of the Premier League. The positive control adopted was Sam Allardyce, who despite being criticised by the estimable Johnny Giles for a lack of "humidity", has proven at this level to be very efficacious if not always immediately attractive – like removing a bunion with a belt-sander.

At Portsmouth and West Ham the placebo proved ineffective in the league, but surprisingly retained its psychological effect in the knockout competitions where it proved more effective than most other products that it was tested against – Steve Bruce, for example.

This is not to denigrate the Sunderland boss, who is the nearest thing the English touchline has seen to Gérard Depardieu. Besides, Bruce was clearly prey to exterior issues that did not effect Grant – not least a slight case of Fems (Future England Manager Syndrome, an affliction that has torpedoed the careers of men from Trevor Francis to Aidy Boothroyd) and a more severe outbreak of PSSAC (Possible Successor To Sir Alex Complaint, which has likewise had an enervating effect on Roy Keane and Mark Hughes).

Steve, I should add, has also shown himself to be one of the few coaches who are verbalistically (as Wenger might say) capable of filling the gap left by Sir Bobby Robson. "The one area of the pitch where we are a threat is the top end," is one splendid Bruceism. While his summarising of the talents of the Benin midfielder Stéphane Sessègnon – "He is a little packet of dynamite" with "a small centre of gravity" – was straight out of the top pocket. In a world in which managers – under the guidance of the FA's new elite-performance director of bland corporate babble, Gareth Southgate – are increasingly given to saying nothing whatsoever in the least interesting manner possible over the longest timeframe, this sort of impish linguistic whimsy is to be welcomed.

So what of the clinical trials of football managers? Some will claim that the tests are flawed due to a whole raft of outside influences that are beyond the control of any coach – referees, luck, Joey Barton, that sort of thing. Others will say that Grant is not the only placebo out there, and that in truth, as far as anyone can judge, every manager is simply an inert pill in a blind test of football faith.