What is a double blind study in research?
Jul 10, 2020 · In experimental research, subjects are randomly assigned to either a treatment or control group. A double-blind study withholds each subject’s group assignment from both the participant and the researcher performing the experiment.
What is the purpose of a double blind placebo controlled study?
Jul 21, 2021 · Keeping both the researchers and the subjects blinded to treatment allows a double-blinded study to prevent the researchers from treating the study groups differently. The double-blinded study minimizes the risk of various types of biases, such as observer bias or confirmation bias, which may influence the results of the investigation.
How many patients should be included in a double-blind trial?
Jan 03, 2022 · Definition of a Double-Blind Study In scientific research, participants are often randomly assigned to one of two groups. In the treatment or experimental group, participants are given a treatment...
What is an example of a double blind experiment?
The best and most reliable form of research is the double-blind, placebo-controlled study. The purpose of this kind of study is to eliminate the power of suggestion. The double-blind study keeps both doctors and participants in the dark as to who is receiving which treatment. This last part is important because it prevents the researchers from unintentionally tipping off the study …
What is a double study?
A double-blind study is one in which neither the participants nor the experimenters know who is receiving a particular treatment. This procedure is utilized to prevent bias in research results. Double-blind studies are particularly useful for preventing bias due to demand characteristics or the placebo effect.Apr 2, 2020
What is the point of a double-blind study?
Double blind studies prevent bias when doctors evaluate patients' outcomes. This improves reliability of clinical trial results. Should you have health complications during a trial, such as a possible drug reaction, your doctor can “unblind” you and find out which treatment you're receiving.
What is an example of a double-blind study?
Medication Experiments A double-blind experiment is beneficial when testing a specific medication. Half of the participants are given the medication, and the remaining participants are given a placebo. A placebo is an inactive substance such as a sugar pill that looks identical to the medication.
How do you conduct a double-blind study?
A double-blind study withholds each subject's group assignment from both the participant and the researcher performing the experiment. If participants know which group they are assigned to, there is a risk that they might change their behavior in a way that would influence the results.Jul 10, 2020
Are double-blind studies ethical?
The point is that double-blinding is ethical only if it serves a scientific purpose. If its real purpose is to keep subjects in the trial when it is not in their best therapeutic interest to remain--a conflict of interest if ever there was one --then the blinds should be lifted.
Does double-blind increase the placebo effect?
Double-blind placebo studies improve on experiments that compare the response of people taking a pill (or other treatment) to those who do not. The problem with these experiments is that they mix up the placebo effect (taking a pill) with the treatment effect (the medication in the pill).Nov 23, 2010
What is triple blinding?
[trip´l blind] pertaining to a clinical trial or other experiment in which neither the subject nor the person administering treatment nor the person evaluating the response to treatment knows which subjects are receiving a particular treatment or lack of treatment; see also placebo.
What is the difference between a single blind and a double-blind study?
In a single-blind study, patients do not know which study group they are in (for example whether they are taking the experimental drug or a placebo). In a double-blind study, neither the patients nor the researchers/doctors know which study group the patients are in.
Which of the following best describes components of a double-blind study?
Which of the following best describes a double-blind study? The participant in the experiment and the person collecting the data are not aware of the specific hypothesis being tested. A population of mental health patients were shown to have suffered abuse as children.
What is blinding?
Blinding means hiding who is assigned to the treatment group and who is assigned to the control group in an experiment .
What is the difference between single-blind, double-blind and triple-blind studies?
In a single-blind study , only the participants are blinded. In a double-blind study , both participants and experimenters are blinded. In a tri...
Why is blinding important?
Blinding is important to reduce bias (e.g., observer bias , demand characteristics ) and ensure a study’s internal validity . If participants kn...
What is the difference between a single- and a double-blind study?
A single-blind study is when participants do not know whether they were assigned to the control group or the treatment group. The experimenter, how...
What is the purpose of a double-blind study?
Double-blind studies are used to increase the validity of experimental results. They accomplish this by minimizing experimenter and participant bia...
What is a double-blind, randomized controlled trial?
A randomized controlled trial (RCT) occurs when participants are arbitrarily assigned to either the control group or the treatment group. That stud...
Origins of the Double-Blind Study
One of the earliest recorded examples of the double-blinded study was conducted in 1784, by Friedrich Wilhelm von Hoven, a government health official in Germany. He wanted to test whether homeopathic drugs, which were popular at the time, were a legitimate form of medicine.
Double-Blind Control
The control group plays an important role in experimental research. As previously mentioned, this group does not receive any special treatment during the course of a study. This group serves to represent how the population behaves in regular, everyday scenarios.
Randomization
Randomization plays a similarly important role in experimental research. Ultimately, researchers are trying to attribute any observed differences between the control and treatment groups to the conditions of the study. To do this, they need to be certain they can rule out other differences that might have influenced the results of the study.
The Process of Unblinding
Researchers frequently assess participants regarding the degree of their blindness. This is often done by asking participants questions about various aspects of the study that were withheld from them. If the participants exhibit no knowledge of this withheld information, then their blinding is considered perfect.
Premature Unblinding
Researchers aim to maximize blindness as much as possible. Premature blindness occurs when participants become privy to information that was withheld about the conditions of a study before it has ended.
Unblinding After the Study
Ideally, unblinding occurs after a study has ended. That way, biases that can arise from premature blinding are avoided. The unblinding of participants is often achieved by debriefing them to inform them of the nature of the study. This is particularly important if deception was used as a way of "blinding" them before the study begins.
What is a placebo pill?
A placebo is an inert substance, such as a sugar pill, that has no effect on the individual taking it. The placebo pill is given to participants who are randomly assigned to the control group.
Why is double blinding important?
A double-blind study can be a useful research tool in psychology and other scientific areas. By keeping both the experimenters and the participants blind, bias is less likely to influence the results of the experiment.
Why do we do double blind studies?
Reasons to Use a Double-Blind Study 1 First, since the participants do not know which group they are in, their beliefs about the treatment are less likely to influence the outcome. 2 Second, since researchers are unaware of which subjects are receiving the real treatment, they are less likely to accidentally reveal subtle clues that might influence the outcome of the research. 1
Why is randomized double blind placebo considered the gold standard?
2 One of the reasons for this is the fact that random assignment reduces the influence of confounding variables.
What does double blind mean in psychology?
As mentioned previously, double-blind indicates that the participants and the experimenters are unaware of who is receiving the real treatment . 1 What exactly do we mean by ‘treatment'? In a psychology experiment, the treatment is the level of the independent variable that the experimenters are manipulating.
What is a control group?
A control group is a subset of participants who are not exposed to any levels of the independent variable. This group serves as a baseline to determine if exposure to the independent variable had any significant effects. Those randomly assigned to the experimental group are given the treatment in question.
Do energy bars contain protein?
All of the bars are packaged the same, but some are sports bars while others are simply bar-shaped brownies. The real energy bars contain high levels of protein and vitamins, while the placebo bars do not. Because this is a double-blind study, neither the participants nor the experimenters know who is consuming the real energy bars ...
What is double blind trial?
Double-blind trials are a form of randomized trials and can be ‘upgraded’ to triple-blind trials, in which the statisticians or data clean-up personnel are also blind to treatments.
Why are double blind trials considered reliable?
Double-blind trials are seen as the most reliable type of study because they involve neither the participant nor the doctor knowing who has received what treatment. The aim of this is to minimize the placebo effect and minimize bias .
What does it mean when a doctor is not aware of the results of a double blind study?
Similarly, the doctors not being aware of the treatments means they do not unconsciously bias their interpretation of the study results.
Why is it important to compare an established drug to a new one?
This allows researchers to compare an established drug to a new one to establish which one is more advantageous. However, unlike double-blind, placebo-controlled trials, they are not very good at statistically evaluating if a treatment is effective overall.
Is Remdesivir a double blind drug?
The antiviral nucleoside analog remdesivir has been tested in several double-blind trials and was the first drug to gain full FDA approval for use against COVID-19 in October 2020. However, the results of trials have been conflicting, and some experts remained unconvinced of its benefits. In November 2020, the World Health Organization recommended ...
Can a double blind study be placebo controlled?
Double-blind trials can come in different varieties. Double-blind, placebo-controlled studies involve no one knowing the treatment assignments to remove the chance of placebo effects. In a double-blind comparative trial, a new treatment is ...
Why is double blind study important?
This last part is important because it prevents the researchers from unintentionally tipping off the study participants, or unconsciously biasing their evaluation of the results.
How many people should be in a double blind study?
A good double-blind study should enroll at least 100 people, preferably as many as 300. Dramatically effective treatments can prove themselves in somewhat smaller trials; however, research involving 30 or fewer people generally doesn't prove anything at all.
What is a double blind comparative study?
A double-blind comparative study is similar to a double-blind, placebo-controlled study , except that instead of placebo, one group receives a standard drug. Therefore, such studies compare a new drug to another that is already known to work. Such studies are especially useful in determining whether a new treatment offers any advantages ...
Why is the last part of a study important?
This last part is important, because it prevents the researchers from unintentionally tipping off the study participants, or unconsciously biasing their evaluation of the results. The purpose of this kind of study is to eliminate the power of suggestion.
What is the best and most reliable form of research?
The best and most reliable form of research is the double-blind, placebo-controlled study. A treatment cannot really be said to be proven effective unless it has been examined in properly designed and sufficiently large studies of this type. In these experiments, one group of subjects receives the "real thing"—the active substance being tested.
Is placebo double blind?
Individuals in both groups don't know whether they are getting the real treatment or placebo (they are "blind"). Furthermore, the researchers administering placebo and real treatment are also kept in the dark about which group is receiving which treatment (making it a "double-blind" experiment).
Why are double blind studies important?
Learn how double-blind studies contribute to the validity of research by reducing the biases of research participants and the experimenters themselves.
What is a double blind experiment?
Double-blind experiments are scientific experiments with a control group and an experimental group in which the participants and researchers are both unaware ...
What are control groups and experimental groups?
Control Groups and Experimental Groups. When researchers design experiments, they typically break the participants into two groups: a control group and an experimental group. The control group of participants does not receive the experimental treatment. In contrast, the experimental group is the group that participates in ...
Can an experiment be double blind?
In fact, sometimes experiments can't be double blind. If the experimenter must be privy to the different treatment of the two groups in order to carry out the experiment, then a double-blind experiment is impossible.
Can you do a double blind taste test?
That's how double-blind experiments work. When Double-Blind Experiments Can't Be Used. It's not always feasible to conduct a double-blind experiment.
Do researchers need to know which procedure they are performing on which individuals?
While they may be able to keep the information from the research participants themselves, the researchers must know which procedure they are performing on which individuals. In these cases, experimenters are likely to use single-blind experiments in which information is only kept from the participants. Lesson Summary.
Can you measure the effects of sports drinks?
You need to measure the effects of both sports drink, which is your experimental group, and water, your control group, and then compare the results. When dealing with human subjects, researchers can't simply tell some participants to be in the control group and some to be in the experimental group.
A Closer Look at Double-Blind Studies
Reasons to Use A Double-Blind Study
- So why would researchers opt for such a procedure? There are a couple of important reasons. 1. First, since the participants do not know which group they are in, their beliefs about the treatment are less likely to influence the outcome. 2. Second, since researchers are unaware of which subjects are receiving the real treatment, they are less likely to accidentally reveal subtle clues t…
Example
- Imagine that researchers want to determine if consuming energy bars before a demanding athletic event leads to an improvement in performance. The researchers might begin by forming a pool of participants that are fairly equivalent regarding athletic ability. Some participants are randomly assigned to a control group while others are randomly assigned to the experimental gr…
A Word from Verywell
- A double-blind study can be a useful research tool in psychology and other scientific areas. By keeping both the experimenters and the participants blind, bias is less likely to influence the results of the experiment. A double-blind experiment can be set up when the lead experimenter sets up the study but then has a colleague (such as a graduate s...
How They Work
Benefits of Double-Blind Trials
- Double-blind trials remove any power of suggestion, as no one involved knows the treatment patients receive. This means that doctors carrying out the study do not know and cannot accidentally tip off participants. Similarly, the doctors not being aware of the treatments means they do not unconsciously bias their interpretation of the study results. The main principle behin…
Covid-19 and Double-Blind Trials
- Double-blind trials are usually needed for drugs and treatments to get approval to be used in many countries. However, good, comprehensive double-blind trials take time and require many participants. This has been especially problematic during the COVID-19 pandemic, as the world has searched for pharmaceutical treatment options to improve survival and for vaccines to prev…
References
- Cancer Research UK. 2019. Randomized Trials. [online] Available at: <https://www.cancerresearchuk.org/find-a-clinical-trial/what-clinical-trials-are/randomised-trials> [Accessed 25 July 2020].
- European Centre for Disease Prevention and Control. 2020. Vaccines And Treatment Of COVID-19. [online] Available at: <https://www.ecdc.europa.eu/en/covid-19/latest-evidence/va…
- Cancer Research UK. 2019. Randomized Trials. [online] Available at: <https://www.cancerresearchuk.org/find-a-clinical-trial/what-clinical-trials-are/randomised-trials> [Accessed 25 July 2020].
- European Centre for Disease Prevention and Control. 2020. Vaccines And Treatment Of COVID-19. [online] Available at: <https://www.ecdc.europa.eu/en/covid-19/latest-evidence/vaccines-and-treatment>...
- Misra, S., 2012. Randomized double-blind placebo control studies, the "Gold Standard" in intervention-based studies. Indian Journal of Sexually Transmitted Diseases and AIDS, 33(2), pp. 131.
- The New York Times. 2021. Coronavirus Drug and Treatment Tracker [online] Available at htt…
