Measuring is different from counting. However, in forensic science the two are often suggested to be the same. This needs to change.
Measuring is the assignment of a number, and all the uncertainties of that of that number, to something. The purpose of assigning a number is to give meaning to the object measured. To give meaning includes:
Knowing the amount of uncertainty contained in the number helps distinguish counting from measuring.
Measuring relies upon estimation. The choice of data, the methodologies employed, and level of quality measures used tells you how confident you can be in the estimation. Once you have a reliable estimation of how close a number may be (or not be) to the true value, you can make informed decision as to what purposes the number can be used – and not used.
Counting is a process of determining the number of elements. It is premised on the being able to identify all the things you seek to count.
Things to Consider
Some things to take into account when making an estimation:
Why This Matter
In sum, a measurement is much more than counting. It is based upon a machine’s indirect count of a substance which results from combining algorithms, and programmed assumptions of a machine’s software. This is known as an uncertainty calculation.
Counting is what you do to get a number. Measuring is what you do if you want to know the truth about the number. Counting will produce a result, but is may not be fit for your purpose in a court room.