Nicola Sturgeon rejected claims she "misled the public" in an angry clash over claims the coronavirus rate was five times lower than in England.
The First Minister said she stands by the view despite the UK’s statistic watchdog warning the Scottish Government should not have made the "uncaveated" comparison.
In their response to the use of the figures, the Office for Statistics Regulation said: "If it is to be undertaken, the results and the uncertainties should be communicated transparently. We do not think that the sources above allow for a quantified and uncaveated comparison of the kind that was made.
"In future if such comparisons are made, we would expect to see sources made publicly available and a clear explanation of the limitations and associated uncertainty."
The rebuke was raised in Holyrood by Scottish Conservative leader Jackson Carlaw, who demanded an apology.
He said: "This isn't just a number, this isn't some statistical pedantry. This was the centrepiece of policy used to justify major decisions just three weeks ago.
"Ministers used it to explain the timing of lockdown being eased … Nicola Sturgeon used this prevalence figure to suggest her policy was working better than elsewhere in the UK."
Carlaw claimed Sturgeon had been "playing politics" to the undermine UK Government.
And in a scatter-gun attack, he brought in a separate row over SNP-branded face coverings and said the party had encouraged people to "shout obscenities" at people coming from England.
Sturgeon said: "I genuinely find myself feeling quite sorry for Jackson Carlaw. I have been a politician for 30 years, and I still cannot imagine getting so bound up in bitter partisan politics that I cannot bring myself to welcome the fact that we have made such progress against a deadly virus. How blinded must he be to find himself in that position? My tolerance of that kind of politics is lower than it has ever been.
"The conclusion that I drew about the relative prevalence of the virus was not wrong."
Two hours later, Carlaw abruptly quit as leader of his party, claiming he'd thought about if over summer and is no longer the person to make the pro-UK argument for the Tories.
