The obvious way to avoid such problems is to agree beforehand on a method that will be used to resolve

them if they arise. Often, the degree of separation between the readings dictates the best approach to

take. Where the uncertainty of each party is significantly different, the party with the lowest uncertainty in

the calibration would be considered more reliable.

The AMTMA offers the following methods as options you can choose from. If the Referee Method fails to

bring a resolution, then the Universal Standard Method should be used due to the fact it is technically

based and internationally accepted by metrologists in all disciplines.

THE REFEREE METHOD

The two parties agree on a third party to provide a referee measurement that it is agreed will be

considered as the actual value. An alternative on this is where the reading by either party that is closest

to that provided by the referee is considered the accepted value.

Other variations of this method include averaging the readings of three or more laboratories and may also

include the readings produced by the parties to the dispute.

Unless otherwise agreed to, the costs of using outside laboratories in this method are paid by the losing

party.

THE UNIVERSAL STANDARD METHOD

National and international standards agencies have produced methods of resolving measurement

disputes that focus on the uncertainty budgets of those that have produced the measurements. The

advantage of this method is that its technical base tends to remove personalities from the equation and

may indicate that neither party to a dispute has the capability required to resolve it.

Using this method, the onus of proving a measurement falls on the party who has questioned the results

of calibration. If requested, this party must provide a copy of their uncertainty budget for the

measurement to the other party for review. Budgets from both parties should be compared. Such a

review should focus on seeking agreement between both parties respecting each element included in the

budget since it will rarely, if ever, be all right or all wrong. The mathematics should take care of the rest.

There may be cases where one or more elements have not been included in the budget and when they

are, the outcome changes significantly.

In the event one or more assumptions in the budget cannot be resolved, a third party can be asked to

provide an opinion on them.

Automation and Metrology, Inc. is a Member of AMTMA