Stormont maturity needed over sore that just won't heal
Reading this study is a little like opening a medical report for someone with a long-running, wasting illness.
The condition hasn't gone away and it is now up to Stormont to decide what medicine we will take, if any.
It shows that the problem isn't curing itself and suggests we can probably live with it, but at the cost of continuing pain and ill health.
We have to decide whether we'd prefer that to treatment, which could itself be radical.
Dr Nolan has been probing this condition for a while. He put together a series of landmark Peace Monitoring reports for the Community Relations Council.
They mapped in forensic detail the fault lines of our uneasy settlement - pointing to areas where it could splinter.
He then moved to the flag dispute, and in this latest study he has commissioned independent research of his own from LucidTalk.
It shows a very complex situation in which the narrowest of majorities across the province would accept or support 18 designated days, the same system that caused all the trouble when introduced in Belfast.
The alternative, which is happening now, is for each of our 11 councils to make its own rules. That creates a winner takes all system, with resentment when nationalist-controlled areas ban Union flag flying on council offices and unionist areas keeping the flag up constantly.
The flags on lampposts issue feeds on this grievance.
Protesters told Dr Nolan they actually didn't like the number of flags on lampposts. Yet they felt obliged to defend them as they felt their culture was eroded by the removal of flags on civic buildings and a perceived attack on other British symbols.
Taking the heat out of the civic display of flags could unfreeze other issues, but it needs leadership from Sinn Fein and the DUP to sell a compromise.
It is tempting for these parties to line up with the most hardline and nervous sections of their own communities, but that will deepen tension, not remove it.
There are possible refinements around flying Irish flags during visits by Southern dignitaries in return for more designated days or the use of civic flags on some occasions.
Whatever the fine detail, we need a protocol on flag-flying which will apply province-wide, allowing unionists to say that the flag flies everywhere at least sometimes and nationalists to feel there is consistency, fairness and agreement about this.