As she delved deeper into her research, Rachel stumbled upon the work of Jum Nunnally, a pioneer in psychometric theory. She discovered his seminal book, "Psychometric Theory," which had been a cornerstone in the field of psychology for decades. The PDF version of the book, readily available online, became her constant companion.
Psychometric theory is concerned with the development, evaluation, and application of psychological tests and assessments. It aims to ensure that these tests are reliable, valid, and fair. The theory is based on mathematical and statistical methods, which enable researchers to analyze and interpret test data. Psychometric theory has numerous applications in various fields, including education, employment, and healthcare. psychometric theory nunnally pdf