POL SCI 3 Lecture Notes - Lecture 17: Inflection Point, Operationalization, Social Desirability Bias
28 Oct 2016
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Document Summary
Extent to which variable groups cases that are the same (vs. varying) in terms of property measures. 1-4 varies in terms of property, especially 4 (huge variation) Collapsing moves measure from ratio to ordinal. Days more sensitive, seconds, nanoseconds even more sensitive. People who are the same (cid:498)years old(cid:499) vary in age in days. 3 point vs. 5 point vs. 101 scale. As number of scale point increase, sensitivity goes up. Extent to which the measure is free from random error. Continuum from low 0 (no reliability) to high 1 (perfect reliability) Reliability is how much information relative to noise low: no info, much. None: measure variable whether male or female (sex) Observed score = true score + random error. Random error = noise, unpredictable things that happen. Operationalization: flip coin in front of each person assign male or female. There is an inflection point at which sensitivity and reliability is the highest.
