1.15:
Reliability and Validity
In a scientific setting, suppose a researcher wants to create a test to measure the compatibility of potential partners on an online dating website. They must consider two important factors to generate successful outcomes.
One is reliability, which refers to the ability of a test—or other research instrument—to provide consistent, and thus, reproducible, results under similar circumstances.
In this context, the compatibility test would be considered reliable if the same people take the test twice and perform similarly each time. This situation is also known as test-retest reliability.
However, getting consistent results does not ensure that a test is accurate. Now, the second factor, validity—the extent to which a test accurately measures or predicts what it set out to measure—must be reflected.
Will they actually enjoy spending time together on a date?
If the pair scored low in dating compatibility and still went out to dinner together, perhaps they had a miserable time. In this case, the test did have high predictive validity—it forecasted the behavior.
In the end, researchers strive for reproducibility and accuracy: here, the test is successful if other incompatible couples continue in misery, while those who share common interests enjoy a fantastic time together.
1.15:
Reliability and Validity
Reliability and validity are two important considerations that must be made with any type of data collection. Reliability refers to the ability to consistently produce a given result. In the context of psychological research, this would mean that any instruments or tools used to collect data do so in consistent, reproducible ways.
Unfortunately, being consistent in measurement does not necessarily mean that you have measured something correctly. To illustrate this concept, consider a kitchen scale that would be used to measure the weight of cereal that you eat in the morning. If the scale is not properly calibrated, it may consistently under- or overestimate the amount of cereal that’s being measured. While the scale is highly reliable in producing consistent results (e.g., the same amount of cereal poured onto the scale produces the same reading each time), those results are incorrect. This is where validity comes into play. Validity refers to the extent to which a given instrument or tool accurately measures what it’s supposed to measure. While any valid measure is by necessity reliable, the reverse is not necessarily true. Researchers strive to use instruments that are both highly reliable and valid.
How Valid Is the SAT?
Standardized tests like the SAT are supposed to measure an individual’s aptitude for a college education, but how reliable and valid are such tests? Research conducted by the College Board suggests that scores on the SAT have high predictive validity for first-year college students’ GPA (Kobrin, Patterson, Shaw, Mattern, & Barbuti, 2008). In this context, predictive validity refers to the test’s ability to effectively predict the GPA of college freshmen. Given that many institutions of higher education require the SAT for admission, this high degree of predictive validity might be comforting.
However, the emphasis placed on SAT scores in college admissions has generated some controversy on a number of fronts. For one, some researchers assert that the SAT is a biased test that places minority students at a disadvantage and unfairly reduces the likelihood of being admitted into a college (Santelices & Wilson, 2010). Additionally, some research has suggested that the predictive validity of the SAT is grossly exaggerated in how well it is able to predict the GPA of first-year college students. In fact, it has been suggested that the SAT’s predictive validity may be overestimated by as much as 150% (Rothstein, 2004). Many institutions of higher education are beginning to consider de-emphasizing the significance of SAT scores in making admission decisions (Rimer, 2008).
In 2014, College Board president David Coleman expressed his awareness of these problems, recognizing that college success is more accurately predicted by high school grades than by SAT scores. To address these concerns, he has called for significant changes to the SAT exam (Lewin, 2014).
This text is adapted from OpenStax, Psychology. OpenStax CNX.