Validity and Reliability of a piece of information? (1 Viewer)

[Lucas_]

Is it the same as for an experiment? How do we do this?

 

[ismeta]

If I've heard correctly, reliability of a piece of information is evaluated by comparing it with other sources - if it agrees with other sources, then it's reliable, but not necessarily valid. Validity, not entirely sure. Sorry!

 

[madharris]

Validity I think is looking at the url ending (e.g. .gov, .com, .edu), looking at the authers and what they're profession is (i.e. are they 10 year olds who posted their class project up or are they uni students doing a phd on it), when was it last revised (e.g. something from 1980 might not be as useful as something from 2010)

And I'm pretty sure as above said, reliability is comparing it to other sources such as text books and comparing info

 

[someth1ng]

Reliability is the consistency of results and the ability for a test to have consistent and similar results.

Example 1:
Aim
Determine the number of apples in a garden.
Method
- Send three students to count apples
- After sufficient time, record the results of their counting.
Result
Student 1 saw 3 apples
Student 2 saw 3 apples
Student 3 saw 3 apples
Conclusion
There were 3 apples in the garden.

This example is reliable since all 3 students recorded the same result.

Example 2:
Aim
Determine the number of apples in a garden.
Method
- Send three students to count apples
- After sufficient time, record the results of their counting.
Result
Student 1 saw 3 apples
Student 2 saw 6 apples
Student 3 saw 9 apples
Conclusion
There were 6 apples in the garden (using the average).

This example is unreliable since all 3 students recorded the different results.

Validity refers to if the results answer the question using an appropriate method.

Example 1:
Aim
Determine if a distant star is being red/blue shifted using spectroscopy.
Method
- Using a spectroscope, measure the absorption lines of a star.
- Compare the gaps of the absorption lines with a table of all the absorption/emission lines of all elements.
- If the lines are shifted towards the red end, it is red shifted and if it is shifted towards the blue end, it is blue shifted.
- Repeat experiment of other spectroscopes.
Result
The star's absorption lines corresponded with those of hydrogen and were shifted towards the red end of the spectrum.
Conclusion
The tested star was being red shifted.

This is a valid experiment since the method of determining results correctly answers the aim/question. It is also reliable assuming that the results were consistent with the following tests.

Example 2:
Aim
Determine if a distant star is being red/blue shifted using a thermometer.
Method
- Read the temperature of the thermometer.
- Using a thermometer, point it towards a star.
- After 10 minutes, measure the reading on the thermometer and record changes.
- Repeat experiment.
Result
After 10 minutes, the temperature changed by 1 Centigrade. Therefore, it is blue shifted.
Conclusion
The tested star was being blue shifted.

This is an invalid experiment since the method cannot determine the red shift but it is probably reliable assuming that the result would be the same if retested.

If you are looking at a piece of information about the number of apples produced in Australia but you use a figure about the number of bananas produced in Australia, it is invalid since it does not answer your aim.
If you are looking at a piece of information about the number of apples produced in Australia and find 3 pieces of information with the identical figures then it is reliable.

In essence, it is the same for validity and reliability for experiments.

I hope this helps!