To my knowledge, standards ISO 1101 (for dimensions) and ISO 14405 (for GTOLs) make no statements whatsoever as to the required number of measurements for evaluation of quantities specified therein. To give one example, if a diameter is to be evaluated via two point measurements, one person might take just one or two measurements which lie within the specified range and consequently label a part as "good", whereas another might carry out ten measurements on the same part, one of which does not meet the specification, and therefore reject it. The same goes for measurements of flatness etc.: The more measurements are undertaken, the greater the risk of receiving an "out of bounds" result.
Hence my question: Is there some standard specifying the number of measurements (maybe depending on part size or other parameters)? I haven't found one so far. Just leaving it at the examiner's discretion would seem strange to me...
