To understand the importance of Precision and Validity measures for any diagnostic test
Precision is best understood by understanding the reproducibility, inter & intra observer variation of any new test and Validity measures accuracy as compared to gold standard in detecting the disease.
To understand the validity measures for diagnostic test
Sensitivity, Specificity, +ve & -ve Predictive value are important validity measures. Validity measure can be estimated from a two by two table comparing the test instruments vs gold standard. Defining gold standard is very important and it is important to critically appraise research article for the good standard of definition.
To estimate Likelihood ratio and apply it in clinical decision making
Clinical decision making based on good history an basic clinical presentation very useful in assessing pretest probability of disease. Using Fagans Nomogram clinical decisions ruling in and ruling out disease can be done effectively.