What is external validity?

what is external validity imagine this scenario let's say a lady is sitting on a park bench when a stranger walks by and catches her interest she would like to make a good impression on him next time she sees him so she decides to do some research she surveys the next group of people she comes across to get opinions on how you make someone fall in love with you the group of people she next comes across as some young children playing in the park she asks them how do you make someone fall in love with you the first child says what works for me is yelling out that you love them at the top of your lungs the second child says I like to wear my superhero suit that gets my friends attention the final boy says give him some through they like chips usually work for me so the lady waits on the park bench at the same time the next day and sure enough her love interest walks by again she summons the wisdom of her survey group and approaches the man [Music] it turns out the results of her survey weren't generalizable to her situation of interest and this is what external validity is about it is the extent to which the results of a study are generalizable to other situations or groups the life struck lady's approach didn't go well as her survey was conducted on a sample that was very different from the target population [Music] good sampling is the key to a study having white generalizability and good external validity here are some features of strong sampling in studies firstly you should ensure a sample is representative of a wider population or at least the population you want to generalize to for example let's say someone is conducting a phase 1 clinical trial to examine the safety of a new drug if they only recruit male Caucasian University students from one Hospital their study will be less generalizable to the wider populations than if they sampled from both genders across multiple ethnicities at multiple sites across the world secondly a large enough group of individuals should be sampled to impart adequate statistical power thirdly any exclusion criteria used in a study should relate to the question of interest if the exclusion criteria are too strict external validity will decrease [Music]

Channel: Dr EW

Views: 37,288

Rating: 4.9431281 out of 5

Keywords: external validity, critical appraisal, clinical trials, critical thinking, basic research

Id: 4jX38E5mtNk

Length: 2min 32sec (152 seconds)

Published: Sun Dec 16 2018