The following questions are important:
- Are they correct? Correctness means that the data were collected according to the exact rules of definition of the metric.
- Are they accurate? Accuracy refers to the difference between the data and the actual value.
- Are they appropriately precise? Precision deals with the number of decimal places needed to express the data.
- Are they consistent? Data should be consistent from one measuring device or person to another, without large differences in value.
- Are they associated with a particular activity or time period? If so data should be stamped, so we know exactly when and where they were collected.
- Can they be replicated? Is the measurement procedure described clearly enough for someone else to be able to replicate the measurement.
The role of data collection in software measurement is illustrated below:ATT- collect->RAW extract->REFINED analysis->DERIVED
RIB-
UTE <-- direct measurement --> <- indirect m. ->Problems occur when something goes wrong and lead to actions:
human error ->fault in x ->failure ->change of x