Measurement: Validity, Reliability, Accuracy (The Basics)

Validity. Data have validity if they accurately measure the phenomenon they are supposed to represent.

Reliability. Data have reliability if similar results would be produced if the same measurement or procedure were performed multiple times on the same population.

Accuracy. Data are accurate if estimates from the data do not widely deviate from the true population value.

So basic, but so important.

From the National Science Foundation – Science & Engineering Indicators 2018 Methodology.

Measurement: Validity, Reliability, Accuracy (The Basics)

Figures are not always facts

The Woman and the Hen

A Woman had a Hen that laid an egg every day. The Fowl was of superior breed, and the eggs were very fine, and sold for a good price. The Woman thought that by giving the Hen twice as much food as she had been in the habit of giving, the bird might be brought to lay two eggs a day instead of one. So the quantity of food was doubled. The Hen thereupon grew very fat, and stopped laying altogether.

Aesop
Aesop’s Fables (find in a library)

Figures are not always facts

What are you measuring?

The gross national product does not allow for the health of our children, the quality of their education or the joy of their play. It does not include the beauty of our poetry or the strength of our marriages, the intelligence of our public debate or the integrity of our public officials.

It measures neither our wit nor our courage, neither our wisdom nor our learning, neither our compassion nor our devotion to our country, it measures everything in short, except that which makes life worthwhile.

—Robert F. Kennedy

What are you measuring?