The OPVL test is a tool to check the reliability of a source according to 5 criteria:
Origin: Where the source comes from.
Ask yourself the following questions:
Purpose: Why does the source exist.
Ask yourself the following questions:
Content: What does the source say?
Ask yourself the following questions:
Value: What value does the source have as evidence?
Ask yourself the following questions:
Limitation: At what point does this source cease to be of value to us as historians?
Ask yourself the following questions:
It is important to note that in OPCVL, you must often consider the Value and Limitation for your Origin, Purpose, and even Content separately.
For instance,
The origin of the source is...
The purpose of the source is...
The source includes...
The values of the origin are...
The values of the purpose are...
The values for the content are...
The limitations of the origin are...
The limitations of the purpose are...
The limitations of the content are...