10 EVIDENCE-BASED MEDICINE trial design double-blind


The way in which a trial is structured, to maximize the opportunity of measuring the effect of the intervention.


Where neither the participants nor those who are organizing the trial are aware of which is the real treatment and which is the placebo at the time the intervention is being administered.


systematic review meta-analysis


An evaluation of the results of all the data on trials related to a particular intervention.


A statistical analysis which evaluates the significance of the results of a number of randomized control trials as if they were one large randomized control trial.


2


randomized control trial randomly assigned control group


active ingredients treatment group placebo effect trial design double-blind


systematic reviews meta-analysis


Ooo oO o Ooo oO oO o


Oo oOoo Oo o


oOo oO Oo oO Oo o


ooOo oO Oo oOoo


Active ingredients and meta-analysis have the same stress pattern.


NB: Current medical practice is moving away from the use of placebo as a comparison in RCTs, for ethical reasons. Instead, a new therapy is entered into a trial against a control, which is normally the current standard treatment for that condition.


Exercise C


Set for pairwork or class discussion. Encourage students to identify elements of the pictures and to speculate on the possible uses. Students should use the highlighted phrases and other words that are useful from the text in Exercise B; they can also use words from Exercise A.


Feed back with the whole class. Accept anything reasonable.


Answers Possible answers:


1 Placebo. Pills and sugar = sugar pills. A non-active treatment (often sugar pills) given to ensure that all patients receive some form of treatment.


2 Randomize. Dice = random. Allocate at random. Randomize the allocation of patients to groups.


3 Systematic review. Library journals with doctor at computer. These are important because they summarize and evaluate all the evidence for a particular intervention.


4 Meta-analysis graph. Provides a summary of the statistical results in a systematic review.


5 Blinding.Woman in blindfold = ensuring that patients are not aware which is the treatment group (receiving the active ingredients) and which is the control group (receiving the placebo).


6 Control group. Patients with syringe covered with stop sign = this group receives the placebo treatment and is used to provide a baseline for the effects on the treatment group.


7 Treatment group. Patients with syringe = this group receives an active ingredient and is used to measure the effect of the treatment.


Exercise D


Introduce the idea of ‘neutral’ and ‘marked’ vocabulary (see Language note below and Vocabulary bank). Set for individual work and pairwork checking.


Feed back, discussing any differences of opinion about whether words are marked, and in what sense they are marked. (Some students may argue that minimal, significant and insignificant are not marked, for example. Others may argue that they are marked, because they suggest not just that something is big/small, but that it is important/unimportant. Compare There is a small problem with the trial and There is an insignificant problem with the trial.)


Answers Model answers:


Neutral


rise, increase fall, decrease


big, large good small Marked 'rocket, soar (v)


co'llapse (v and n), 'plummet (v), plunge (v and n), slump (v and n)


e'normous, huge, 'massive, sig'nificant, tre'mendous* (adj)


'brilliant, out'standing, su'perb, tre'mendous* (adj)


insig'nificant, 'minimal (adj)


* tremendous can mean both very large and very good, so students may place this word in either category


Language note


One way of looking at vocabulary is to think about ‘neutral’ and ‘marked’ items. Many words in English are neutral, i.e., they are very common and they do not imply any particular view on the part


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