A 2014 report from the Scottish Police Authority said Police Scotland should ensure its use of stop and search was proportionate across Scotland, “targeted at the right people, right place and right time”.

It is important care is taken, it said, to ensure particularly communities are not being “disproportionately impacted” by stop and search activity.”

But disproportionate use of stop and search is exactly what is suggested by the police’s own figures on this controversial tactic. Researchers from the Scottish Centre for Crime and Justice Research have identified that police use of stop and search appears far from impartial.

If you are black, you are twice as likely to be stopped and searched, as someone who is white, the figures show, and if you are from a gypsy traveller background, five times more likely.

It is important to note the caveats. The researchers themselves point out the numbers in the study were small, so introducing considerable margin of error. The number of searches carried out on non-white people is relatively low, so there is a reason to be cautious about drawing conclusions from them.

In addition, the reasons for the discrepancy in the rates at which different groups are stopped could be related to behavioural or cultural issues. Low numbers of Asian and Indian people stopped could reflect very different drinking habits among those who are Hindu or Muslim, for example.

But there are few obvious justification for the “ethnic disparity” identified by researchers. There is not generally thought to be a relationship between ethnicity and offending.

And overall Police Scotland’s searches of non-white citizens result in fewer seizures than those of white people, while “success” rates of stop and search are similar for white people and people categorised as black/African.

If, as the researchers say, inconsistencies about the use of searches by age “may indicate a lack of fairness and effectiveness”, then this applies equally to inconsistencies relating to race.

Significantly, given that this controversy began over excessive use of stop and search against young people, searches involving people under 16 and people aged 16-20 were both significantly less likely to result in a seizure than searches of someone aged 21-45.

As a result of public concern, this year will see the end of so called “consensual” searches and a demand that Police Scotland report regularly to the SPA about who is being stopped and why.

The force will now have to provide much better more transparent records and this research will be used to help benchmark what fair and consistent use of the tactic would look like.

In terms of age, gender, ethnicity or geography it should soon be possible to see very clearly that stop and search is serving operational purposes, aligned to the risk of offending and nothing else. These new findings suggest we may have a way to go yet before that can be assumed.