Question

In 1856, John Stuart Mill presented three methods of hypothesis formulation in disease etiology: method of difference, method of agreement, and method of concomitant variation. Which of the following best describes the method of agreement?

		When the frequency of a health problem is different between two places, times, or circumstances, then there is evidence that the health problem is caused by a factor that differs between them
		When the frequency of a factor varies in direct proportion to the health problem, then there is evidence that the health problem is caused by that factor
		When a single factor is common to places, times, and circumstances in which the health problem is common, then there is evidence that the health problem is caused by the factor
		When a factor is associated with a health problem in multiple investigations, then there is evidence that the health problem is caused by the factor
		When a factor is shown to have a strong association with a health problem, then there is evidence that the health problem is caused by that factor

Answer 1

ANSWER: when a single factor is common to places,times and circumstances in which the health problem is common,then there is evidence that the health problem is caused by the factor

John stuart mill's Direct method of agreement is! of two or more instances of the phenomenon under investigations have only one circumstance in common, the circumstance in which alone all the instances agree, is the cause (or effect) of the given phenomenon. → The answer can be understood by the above statement.