4 ways to get the results without the bias
Your brand-new car has a scratch on it. It’s a small one, located just above the left rear tire. The scratch is maybe two inches long … and it’s all you can see.
There are many instances in our personal lives where one single detail can overshadow everything else and if that detail is negative, suddenly the picture as a whole is so much less valuable. The same principle can be true in our professional lives as well, particularly if we’re working on a clinical trial and we have concerns of bias. Because if bias is allowed to sneak its way into the subject of all our hard work, well, that’s a mighty big scratch.
Protecting against potential bias in a clinical trial is a constant challenge for trial managers, and while no two trials are exactly the same, there are some things you can do to minimize your risk of bias. Employ the following four steps in your next trial and you have a better chance to keep it free from bias — or scratches.
1. Ask the right questions. The initial screening surveys you conduct to find subjects for your trial can actually sway heavily toward bias if you’re not careful. Formulate your questions and then review them again, looking for questions that limit a subject’s ability to answer. For example, if you’re looking for people who have been diagnosed with kidney or liver cancer, your question should reflect that. Don’t simply ask them if they’ve ever had kidney cancer; doing so would give them no opportunity to discuss their liver cancer.
2. Establish concrete randomization. Randomization is one of the easiest ways to remove bias from a clinical trial, but your strategy here should hardly be random. Establish a plan and employ one of the randomization strategies below.
* Simple randomization. This is randomization accomplished through random assignments via a simple sequence, such as flipping a coin or rolling a die to determine outcome. In the clinical trial world, computer-generated numbers can be used to provide random assignments and eliminate concerns of bias.
* Block randomization. Block randomization places enrollees in random sample groups, or blocks, to ensure comparable data is delivered from each segment. Simple randomization can be used to assign people to their blocks, and block randomization can prevent one group from skewing the results unfairly.
* Stratified randomization. Stratified randomization is used to balance out covariates like age among test subjects, thus ensuring that the group isn't skewed by too many subjects with common covariates. Stratified randomization works well in small clinical trials but becomes less effective when too many different covariates are present.
3. Go blind. Adding a blinded component to a clinical trial has proven to be an effective way to prevent biased results. Single-blind trials bar subjects from knowing which group they are in until the trial is over, while double-blind trials hide the group affiliation from both the participants and the investigators until the trial has concluded.
4. Report everything. Even at trial's end the possibility for bias still exists. When it comes time to report the findings, we are all naturally drawn to report the most interesting and significant findings first. There’s nothing wrong with that, of course, but too often some of the other, deemed lesser, findings are ignored and never see the light of day. To eliminate reporting bias from your clinical trial, everything should be reported, no matter the significance. It’s the only way to tell the whole truth without any biased strings attached.
Meta Description: Learn how to keep bias out of your clinical trial with these four tips.