Calculate index selectivity = distinct values / total rows. High selectivity (close to 1.0) makes an index effective; low selectivity means a full scan is often faster.
Enter the values for the patient or scenario you are assessing. Calculate index selectivity = distinct values / total rows. High selectivity (close to 1.0) makes an index effective; low selectivity means a full scan is often faster. Use the index selectivity result to inform your clinical assessment.