United head into Saturday's Old Trafford encounter with West Brom seven points clear of Manchester City, but a 4-3 Boxing Day triumph over Newcastle means United have now conceded 28 Premier League goals, more than in their entire title-winning campaigns of 2007, 2008 and 2009.
They have conceded 38 goals in all competitions and kept just four clean sheets, and Ferguson said: "You analyse it in every possible detail and try to get a constant thread that tells me we have to do this or that - and it just doesn't appear."
He added: "Either we should not attack at all, which is not going to be Manchester United or just let our supporters live through the agony of 4-3s. We have not had a 5-4 yet or 6-5. That would be more exciting."
It could be argued that such niceties as defending do not matter anyway given United's current status. The argument is not one that Ferguson is convinced by.
"Of course it matters," he said. "If we are scoring four goals at home, it should be one against us or none. It is obviously a concern because it is testing us right to the very limit and making us play beyond the energy levels we need to."
Yet Ferguson has a growing sense that no matter what he says, or which different combination of defenders he comes up with, nothing is going to change.
"I said after the Reading game that it had to stop. It hasn't," he said. "Now I am saying it again. It has to stop. But it won't. It is just one of those seasons when we seem to be giving away silly goals."
Injuries have disrupted Ferguson's team selection often, apart from a couple of brief spells, he has never been able to choose the same back four.
Yet remarkably, two of the defensive mainstays, Jonny Evans and stand-in skipper Patrice Evra have both contributed four goals to the United cause, a number exceeded by only Robin van Persie, Javier Hernandez and Wayne Rooney.
Source: PA
Source: PA