Perceptions or assessments of behavior can be difficult to quantify. When attempt is made to quantify specific actions that are perceptions then a scale is used to measure the behavior on a scale such as a Likert scale with values on a 1-5 scale. One such assessment could be an assessment of pain in which the Likert scale could measure the amount of pain (Severe, Mild, low-grade). Once such a question and scale are created, a diverse variety of subjective assessments can be captured and compared. This holds mostly if the scale is kept the same and the question is kept the same.
This graph was photographed in a TEDx MIT talk. Consider the image that shows the amount of pride that each country inhabitants have in their car. How is this possible to generalize over billions of people?
Using a scale that asks the question to many people in one country enables the collection of data. This data is then averaged by country and then compared through a graph.
This graph thus shows that Italians may make great cars but are less in their relative pride of their car compared to Kenyan’s. Is that true for all people? Definitely not! But it does enable comparison of diverse behaviors that were hard to measure in any other way.