He even sent out amended advice to his members, and emailed Marian School's results for publication in today's Herald on Sunday.
Coulam shows a refreshing intellectual honesty. Too often, the debate about publishing school results has been dominated by politicians seeking easy wins in the opinion polls, and principals more interested in protecting their positions than protecting their pupils.
At the Ministry of Education, it is doubtful any official believes this data provides authoritative comparisons between children's writing ability in Kaikohe and Bluff. When the ministry was asked to name an education expert who could explain the scheme's benefits, an adviser just laughed.
After categorically assuring schools their data would be published as they supplied it, Education Minister Hekia Parata's officials immediately set about fiddling the data to fit into identical boxes - facilitating the construction of ranked league tables.
On the other side, principals sent out an emotive form letter warning that comparing schools would be "potentially harmful to students". The Auckland Primary Principals Association issued questionable legal advice on how schools could get out of disclosing their results.
In fact, buried within the national standards dross is valuable information about how boys are struggling, the decline in writing skills, and Pacific children getting lost at the back of the classroom.
If the idealogues on either side would stop to think, they might realise it is better to intelligently discuss pupils' results than try to hide them.
That, after all, is what it's all about - the kids.