The struggle of measuring the mind: an historical review of psychological measurement from the Ferguson Committee to Steven’s Solution

This thesis looks at the ongoing problems with psychological assessment by looking at how it has changed over time, from the early 1900s to now. It starts by talking about how psychology first tried to measure things such as mental phenomena, and how social issues, including how people feel about race, IQ, and objectivity, affected this. The advent of psychometrics and the widespread use of IQ tests brought up ethical issues. This led to the founding of the Ferguson Committee, which aimed to standardize measuring methods and deal with cultural bias in psychological tests. Even though they tried, they couldn't come to a consensus on significant disputes and theoretical limits, especially when it came to measuring subjective experiences. The thesis then looks at Stevens' important solution, which changed the way we think about measurement by defining it as giving numbers according to certain norms and introducing the four scales of measuring: nominal, ordinal, interval, and ratio. Stevens' framework gave modern psychological research useful tools, but it also got a lot of criticism for making traditional scientific ideas about measurement weaker and encouraging questionable methods connected to construct validity and replicability. The ongoing arguments over fairness, methodological rigor, and scientific legitimacy show that psychological measuring is not only a technical task; it is also a deeply moral and philosophical one. The study's conclusion is that a thoughtful, historically informed, and socially conscious approach is still necessary for both the science and practice of psychological measurement to move forward.