A good randomised controlled trial normally uses a placebo.
A placebo is an inert medication or treatment which yields no medical value.
A placebo is used in a clinical trial to compare its lack of effect to the actual effect of the active drug or treatment being studied.
However, much evidence has supported the effectiveness of a placebo in a range of situations (known as "placebo effect").
For this reason, study placebos are "blinded" to try and avoid the "placebo effect".
The aim of "blinding" is to make the study participant unaware of whether they are receiving placebo or trial medication / therapy.
Recognising that all research has flaws and, of course, where ethically appropriate, the "gold standard" for clinical trials is considered to be a multi-centre (involving multiple institutions for comparison of what should be reproducible data), double blind (this means neither clinician nor study participant know whether they are receiving/giving an inert treatment or medication), randomised (a process that assigns equally eligible study participants completely by chance, rather than by choice, to either an active treatment group, a control group and/or a conventional treatment group), placebo controlled trial.
Critiquing research involves many aspects relating to the design, conduct and analysis of a study.
The "gold standard" elements of a particular study will be considered first.
These elements normally form part of the title, so this seems like a good place to start.
Didgeridoo playing as alternative treatment for obstructive sleep apnoea syndrome: randomised controlled trial Multi-centre - This was a single centre study with only 25 study participants.
Double blind - Blinding of subjects would have been impossible because group allocation would have been obvious, due to a lack of placebo.
Sleep study assessors were blinded where possible.
Absolute blinding of all assessors would have been preferable.
Randomise - STATA software(STATA 8.
2, College Station, Tx) was used to generate the randomisation list, which was hidden from the didgeridoo instructor and recruiting physicians.
The didgeridoo instructor used a central telephone service to obtain group allocation.
Placebo Controlled - The authors acknowledge that a limitation in the control group was the lack of placebo, as a mock didgeridoo intervention would have been difficult.
Also acknowledged by the authors was the highly motivated nature of the active didgeridoo group.
This raises suspicion that the Epworth Sleepiness Scale (used to assess the extent of daytime sleepiness) could have produced a marked "placebo effect" among this group.
Furthermore, numerous specialists have questioned the reliability of this scoring system that, incidentally, displayed the strongest positive effect in the trial.
Reference BMJ 2006;332:266-270 (4 February), doi:10.
1136/bmj.
38705.
470590.
55 (published 23 December 2005)
A placebo is an inert medication or treatment which yields no medical value.
A placebo is used in a clinical trial to compare its lack of effect to the actual effect of the active drug or treatment being studied.
However, much evidence has supported the effectiveness of a placebo in a range of situations (known as "placebo effect").
For this reason, study placebos are "blinded" to try and avoid the "placebo effect".
The aim of "blinding" is to make the study participant unaware of whether they are receiving placebo or trial medication / therapy.
Recognising that all research has flaws and, of course, where ethically appropriate, the "gold standard" for clinical trials is considered to be a multi-centre (involving multiple institutions for comparison of what should be reproducible data), double blind (this means neither clinician nor study participant know whether they are receiving/giving an inert treatment or medication), randomised (a process that assigns equally eligible study participants completely by chance, rather than by choice, to either an active treatment group, a control group and/or a conventional treatment group), placebo controlled trial.
Critiquing research involves many aspects relating to the design, conduct and analysis of a study.
The "gold standard" elements of a particular study will be considered first.
These elements normally form part of the title, so this seems like a good place to start.
Didgeridoo playing as alternative treatment for obstructive sleep apnoea syndrome: randomised controlled trial Multi-centre - This was a single centre study with only 25 study participants.
Double blind - Blinding of subjects would have been impossible because group allocation would have been obvious, due to a lack of placebo.
Sleep study assessors were blinded where possible.
Absolute blinding of all assessors would have been preferable.
Randomise - STATA software(STATA 8.
2, College Station, Tx) was used to generate the randomisation list, which was hidden from the didgeridoo instructor and recruiting physicians.
The didgeridoo instructor used a central telephone service to obtain group allocation.
Placebo Controlled - The authors acknowledge that a limitation in the control group was the lack of placebo, as a mock didgeridoo intervention would have been difficult.
Also acknowledged by the authors was the highly motivated nature of the active didgeridoo group.
This raises suspicion that the Epworth Sleepiness Scale (used to assess the extent of daytime sleepiness) could have produced a marked "placebo effect" among this group.
Furthermore, numerous specialists have questioned the reliability of this scoring system that, incidentally, displayed the strongest positive effect in the trial.
Reference BMJ 2006;332:266-270 (4 February), doi:10.
1136/bmj.
38705.
470590.
55 (published 23 December 2005)