Howard Webb, Penalties, and Manchester United
Let's be clear before we start: I'm a Liverpool fan, and I don't like Manchester United. But despite that, this is a simple presentation of facts, and hopefully not some bitter tirade or conspiracy theorist's wet dream. Having read various interesting statistics recently, I thought I'd do a little research (via the excellent Transfermarkt site) and present the numbers; what you make of them is up to you.
For starters, in his 384 match career to date, Howard Webb has awarded sixty penalties, which equates to one every 6.4 games. If we limit the data to English football (or at least the levels of English football that United appear in; Premier League, FA Cup, League Cup and Community Shield), then his record of 46 pens in 285 games is equal to a slightly more frequent rate of one penalty awarded every 6.2 games.
In the 40 Manchester United matches Webb has taken charge of in all competitions, he has awarded them ten spot kicks (or one in every four games) and two to the Red Devils' opponents (one per twenty matches played, as I'm sure you could figure out).
This means that 16.7% of the penalties that Webb has awarded in his career have gone to United, though they have only appeared in 10.4% of his matches, whilst their opponents account for just 3.33% of his penalties from the same proportion of games.
Of course, as the dominant team in English football over Webb's career period, it's natural that Manchester United will receive an above average amount of penalties. They spend more time attacking than virtually every other team out there, so it's unfair to compare their figures with those of the lesser teams that Webb will have officiated.
Looking at United in isolation, since the start of 2004/05 they have been awarded 46 penalties in the Premier League, and had 23 given against them. In other words, one awarded for them every 6.6 games, and one against every 13.2.
However, Howard Webb has given them nine penalties in 32 games (which, as an aside, is more matches than he has officiated for any other side in the top division in England) with just two against. That’s one in their favour every 3.6 games, with one against every 16.
It is therefore fair to say that Webb does award United an above average amount of pens, and is less favourable towards their opponents in this respect than the remaining referees are.
Webb is also less favourable to United's four major rivals (Liverpool, Chelsea, Arsenal and Manchester City) than other refs are when it comes to awarding penalties in their favour too, as can be seen in the table below:

Aside from Manchester City, United's three other major rivals have penalties given against them more regularly with Webb than with other refs as well. It's interesting to note that whilst the five teams here are all awarded penalties at roughly the same rate by other Premier League whistlers (between a range of just one per 6.36 to 7.35 matches), for Webb it varies wildly between 3.55 and 12.50.
Penalties are obviously just one facet of the game, so it would be interesting to research this issue further; both with regards to bookings for instance, but also to see which refs are the harshest upon United and the other big teams. After all, even if Webb does favour United, then there must be refs who don't, right?

Update:
Following the posting of this article, I received several requests for the raw data that fed into the above table to be included here as well. The table below is for Premier League games only. Hopefully it is self-explanatory...

What we can see is that from eight seasons of Premier League football, Webb has awarded the teams at least one penalty in:
6 seasons - Manchester United
3 seasons - Liverpool and Manchester City
2 seasons - Arsenal and Chelsea
Whilst United have never gone more than one season without a Webb awarded spot kick, and Liverpool no more than two, the other three have all had four-year runs without one, with Manchester City going five!
I think the strangest figure falls to Chelsea: just one penalty awarded by Howard Webb in 21 matches since August 2005. Only two were given against in that period too in fairness, though both came in one match against a certain Salford based side....
Related articles you might like:
Who’s The Ref? – The Liverpool stats (cards and penalties) for various refs.
Ref Justice – A look at how the men in black have been treating the Reds in 2012/13 (Hint: Not well...)
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