A double-blind experiment is an experimental method used to ensure impartiality. When both the researcher and the patient are ignorant to the actual ingredients, therefore the trial is completely unbiased. I believe this method is a better way to carry out a trial because the researcher can subconsciously influence the experimental outcome. ACcidentdently, letting the patient know about what substance they are receiving can skew the results of the experiment. Even though scientists are honest people, some might favor a patient receiving the drug vs the placebo, this can also skew the results. Or if a scientist is part of a huge company or fighting for a grant they might generate positive results to fall ahead; this can all be avoided by a proper double-blind study. Manipulations of results are fatal for a drug trial and the health of future users and a double-blind study does a better job of keeping all aspects unbiased.

In a single blind study, only the investigator knows what is to be used on the subject, this has its advantages since the investigator in this case has complete control over what is given; however, this can also induce some bias from either the investigator him/herself or the subject should the investigator do a poor job in hiding the contents of the test. A double blind study is meant to remove this bias since neither investigator nor subject knows what is being administered. Since neither party knows of the contents of say, a new drug, the study can progress without the fear of skewed results. Furthermore, although the subject will have to sign a consent form, they will not know whether or not they are receiving a placebo (if there is one). That way, the subject's own beliefs will not hinder the results and "truer" data can be extracted in this manner. The only downside may be that the investigator will may not know what to do in the case of certain mishaps or effects; however, it is implied, given that there is a human subject involved, that someone in the vicinity such as a head researcher is nearby in order to oversee the double blind study. For a intents an purposes, a double blind study appears to be the optimal way to achieve unbiased results in a clinical trial.

In my opinion double blind studies are more accurate as it sets a reliable baseline for the trial. As an example from the lecture would be the double blind multi-center study. In this example Dr. Simon shows that a doctor's competence affected the study and since it was a multi-center study and double blind you can prove that the baselines were all relatively equally as bias from patient and surgeon were removed in this scenario. However, if this study were to be single blind then the surgeon bias would have to be accounted for and the statistical significance in comparing the multiple centers would decrease. Applying this same logic to the Alzheimer's example given if any of the investigators have a financial incentive for the drug to do well, this could introduce a bias into the study that would not be present if it was conducted under double blind conditions and the investigators are not aware of the placebo vs. experimental dose.

The purpose of double blind studies is to prevent bias due to demand characteristics or the placebo effect. In the case of investigating the effects of a drug that cures Alzheimer’s a double-blind study is beneficial compared to a single blind study. The participants are not aware if they received a placebo or a real drug, therefore their option on the treatment will less likely influence the outcome. In addition, the double-blind study eliminates the chance of the researcher affecting the outcome because they too are unaware of which participants received the placebo vs the real drug. In a single blind test, the researcher is aware of what is given to the participant therefore they can inadvertently reveal clues to the participant which might alter the outcome. The double-blind procedure is more of a precautionary stance to not affect the outcome of the research due to experimenter bias.

Reference:
https://www.verywell.com/what-is-a-double-blind-study-2795103

I can understand your hesitation on working with a double blind study. However, a double blind study at times is necessary to obtain clear unbiased results. There have been times where studies have been manipulated by doctors or principal investigators. This can occur due to immense pressures on researchers to provide positive and conclusive results. Thus, researchers will try to sway the data results. In double blind studies because neither the doctor nor the patient knows, there will likely be no inkling of bias in the results. Most double blind studies are done for drug testing.

A double-blind study is necessary in cases where the investigator may become biased if they had knowledge of which is the effective drug. For the example presented in the question, with a drug to treat Alzheimer's the investigator may selectively distribute the drug. In the unlikely case that they personally know someone in the study, they may choose to give that person the effective drug because they want them to be treated. Additionally, the investigator may skew the results and not randomize the distribution so that their data is favorable to the hypothesis.

In most cases, double blind studies are an effective way of performing a research study and learning new information about a drug or new treatments. Double blind studies are also a way of removing bias from the testing of these drugs. Any previous knowledge that an investigator may have can affect on the outcome of how the new drug is analyzed. In the case of Alzheimer's mentioned above, there are many benefits to conducting a double blind study. Psychologically, neither the patient, nor the investigator can tell if the treatment received is a placebo or a real drug and therefore it cant affect the outcome of the study. It is evident that the main reason double blind studies are conducted is to prevent bias from both parties. This can only be done by removing all certainties that come with performing a single blind study. Although this increases liabilities, it is an effective way of eliciting effective results.

The biggest determining factor in performing a single or double-blind study is the feasibility of doing so. While a single-blind study is almost always possible to perform, there are a number of reasons why it may not be feasible to perform double-blind therapy. For example, at my lab, we administer real and placebo therapies to patients to study the overall effectiveness of a certain therapy. Because the real and placebo therapies have critical differences, the researcher will always be aware of which one they are administering, making it impossible to have a double-blind study. This introduces possible bias in the results but is unfortunately unavoidable.

When there is a device or pill being tested that can be administered without experimenter knowledge, a double-blind study is the superior option, particularly if those same researchers will be involved in statistical data analysis.

I think that having double blind experiments are beneficial in their way since it reduces the possibility of a bias from both the subject and the administrator. This ensures that the results read in by the administrator is not tainted or affected by assumptions or expectations made. In this way, only the observations or the effects that manifest will be the only true result for a test. This will truly show if the results are valid and if the product really works. It is not necessary but it would be a good way to conduct an experiment. However, it is difficult to run due to the coordination that must take place to make sure that the unknowns are kept that way.

In your case, Let us say that there is a new pill developed to treat Alzheimer's. In the clinical trials, generally with an existing medicine or placebo, the new pill is tested and is it will be a randomized control test. If the doctors do not know which participant gets what, the results concluded by them are based on the findings from the test but without any information about the drug which was administered to the participants. Now, these results are analyzed by the investigators and hence not biased. Now with the single-blind case, The doctors would be expecting results based on the drugs that are administered the groups. This creates a bias in the study and unexpected results or outcomes are generally overlooked. Also, adding onto Ibraheem's post, double-blind study is feasible if the study involved in many investigators or labs. When its a study only in a single lab, more often than not, the investigator gets information and hence the test becomes single-blinded.

Double blind procedure is a method of enhancing internal validity in an experiment. In double blind procedure, neither the researcher nor the subjects are made aware of which group is the experimental group and which the control group.

In double blind procedure, experimental group in a clinical study is the group which receives the actual drug or treatment being studied. Controls, double blind procedure, and randomized testing are used to reduce error, self-deception and bias.

Control groups are used in controlled experiments to curb bias. The control group and experimental group must be identical in all relevant ways except for the introduction of a suspected causal agent into the experimental group.

In a double-blind procedure in clinical trials: two identical groups of patients are compared, one of which receives the drug and one of which receives a placebo. Neither the patients nor the doctor know which group receives the real drug, which serves to curb bias. Double blind procedure prevents the researcher from communicating expectations or the subjects acting in ways they think to be expected of them.

The double blind procedure is part of the scientific method that is used to prevent research outcomes from being 'influenced' by the placebo effect or observer bias. Double blinded research is used in many fields of research, including medicine, psychology, social sciences and forensic research. For example, in blind taste tests, where the brand identities are concealed, consumers may favor a different brand.

Many journals use stringent double-blind procedure, in which neither referees nor author(s) are informed of each other’s identity. Double-blind review is based on the principle that criticism is more impartial when authors’ identities are unknown to referees, who might be swayed in either positive or negative directions by authors’ reputations, personality traits, etc. A similar process is normally applied to grant proposals (Kassirer and Campion 1994). Few journals in the atmospheric sciences, for example, use double-blind review. But, many scientific communities are small enough that even double-blind referees and authors can often guess each other’s identity.

While double-blind review may not prevent authors and referees from guessing each other’s identities in a small field (and wrong guesses can turn out to be even more harmful than right ones).

In a single blind method, the individual subjects do not know whether they are so-called "test" subjects or members of an "experimental control" group. Single-blind experimental design is used where the experimenters either must know the full facts or where the experimenter will not introduce further bias. However, there is a risk that subjects are influenced by interaction with the researchers - known as the experimenter's bias. Single-blind trials are particularly risky in psychology and social science research, where the experimenter has an expectation of what the outcome should be, and may consciously or unconsciously influence the behavior of the subject.

http://sociologyindex.com/double_blind_procedure.htm

I agree with the consensus here. Double blind study will produce a more reliable/unbiased result because the data that will be collected is based solely on observations by the investigators. I think that if the investigator has prior knowledge as to who got placebo or the actual drug can affect their judgment when recording results; because in a way they are looking or waiting for something to happen to the subject that got the actual drug. They can become biased on their approaches to the study for each subject. Also, double blinded studies prevents tampering of results because if the investigator wants a certain result for a drug due to ties, or not so good relationship, with the company conducting the research they can definitely influence the results based on their liking.

The double blind study is more important in a clinical trial because it prevents the researcher from influencing the outcome of the experiment.
Double-blind studies improve on experiments that compare the response of people taking a drug (or other treatment) to those who do not. Even though, neither the investigator nor the ones taking the experiment drug know if it is a harmless pill. In this case, the danger of investigator nonverbally communicating their expectation that the drug in clinical trial will work or not is overcome.

In my opinion, the double-blind studies are more important. Double-blind studies are experiments in which the participants, the experimenters and the people analyzing the results do not know who is in the control group. Double-blind studies are frequently used in medicine.

The advantage of a double-blind study lies in the fact that because nobody involved is aware of who is receiving the genuine treatment and who is receiving a placebo, there is a better chance of the study yielding meaningful results. If the treatment being tested is effective, experimenters are more likely to see a clearer indication of this when using this method.

The double-blind procedure helps minimize the possible effects of experimenter bias. Such biases often involve the researchers unknowingly influencing the results during the administration or data collection stages of the experiment. Researchers sometimes have subjective feelings and biases that might have an influence on how the subjects respond or how the data is collected.