This document discusses assessing measurement quality in quantitative studies. It defines key terms like quantitative data, quantitative research, and quantitative analysis. It also discusses principles of measurement, advantages and errors of measurement, and criteria for assessing instrument quality including reliability, validity, sensitivity, and specificity. Reliability refers to consistency and includes stability, internal consistency, and equivalence. Validity refers to measuring what is intended and includes face, content, criterion-related, and construct validity. Sensitivity and specificity refer to instruments' ability to correctly identify cases and non-cases.

1. Assessing Measurement quality in quantitative studies. Presented By: Mrs. Christy Simpson Professor, Maternity nursing

28. Urinary cotininie level Sensitivity = A/(A+C) = .50, Specificity = D/ (B+D) = .83 ( Percentage) Positive predictive value = A/(A+B) =.67 Negative predictive value =D/(C=D)=.71 Likelihood ratio –Positive (LR+) = Sensitivity/(1- Specificity) = 2.99 Likelihood ratio – Negative(LR_) = (1- sensitivity) / specificity =.60 LR Summarizes the relationship specificity and sensitivity in a single number. Self Reported smoking Positive Cotinine Negative Cotinine Total Yes , Smoked A (True positive) 20 B (False positive)10 A+B =30 No,Did not smoke C (False negative)20 D(True negative)50 C+D = 70 A+C=40 B+D=60 A+B+C+D 100