Best practice standards?

The test stations have no control over the age of vehicles presented for test.
What test stations do have is control of how tests on these vehicles are conducted.
Older vehicles and high mileage ones have more faults and may get missed for one reason or another and that becomes a risk.
DVSA are saying if a test station are doing older vehicles or high mileage then the test station might need to take action to reduce the risk and do something about it.

One example may be for the test station to organise the mot schedule and allow more time so a through test and documentation can be done, for example a 1982 converted transit camper van with a combined 12 rfr"s and a page full of advisories to enter into the vts device is going to take time, if the schedule is not managed cram all that into 45 mins( which is not clever) of even an hour,the tester is going or may miss something make mistakes. Make wrong decisions and ends up with appeals, that's the risk.

Its not about turning the vehicles away its all to do with managing the scheme and using certain elements to highlight areas of the risk assessment as a tool to help the test station and testers.
Control the way the tests are carried out and then the risk is minimal.

This is what happens when statistics are used as a management tool - It is a cost effective way of managing (that is why dvsa do it) but it has fundamental flaws.

It has always struck me as a bit odd that there is apparently less risk if you test late vehicles and wizz through them than if you have to test something quite a bit older that you take your time on.

The site assessment outcome isn't necessarily affected just because the score for a VTS testing older vehicles may be lower.

Lots of other stats are factored in such as the overall failure rate at the VTS, and also the failure rates for individual items.

For example, a site with an average vehicle age of 10 years, with a corresponding higher than average overall failure rate, and higher rates for components such as steering and suspension (worn ball joints etc) and corrosion\bodywork may fare no worse than a site testing newer vehicles with corresponding lower failure rates.

The VE's scores during a site assessment visit are only part of the overall equation, with a lot of stats from performance reports being factored in to give the final outcome.

Don't get too hung up about a lower score for vehicle age alone.

What colour are you jock. I presume green as you have had a DBA.

where i work,i test a lot of cars which are older than 10 years but are as in as good a condition as a new car, which kinda makes things tricky i suppose. what do you think?

I got a call because I got the dreaded three stars and failed about 68% one month

"why is your failure rate 68% when the national average is 40something"

"because 68% of the vehicles had defects"

"But your failure rate is so much higher than the average, how do you explain that?"

"I have only worked here so I can't tell you what the other garages are up to"