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Evid Based Nurs 5:64 doi:10.1136/ebn.5.2.64-a
  • Glossary

Glossary

Blinding (masking):

in an experimental study, refers to whether patients, clinicians providing an intervention, people assessing outcomes, and/or data analysts were aware or unaware of the group to which patients were assigned. In the design section of Evidence-Based Nursing abstracts of treatment studies, the study is identified as blinded, with specification of who was blinded; unblinded, if all parties were aware of patients' group assignments; or blinded (unclear) if the authors did not report or provide us with an indication of who was aware or unaware of patients' group assignments.

Concealment of randomisation:

concealment of randomisation is specified in the design section of Evidence-Based Nursing abstracts of treatment studies as follows: allocation concealed (deemed to have taken adequate measures to conceal allocation to study group assignments from those responsible for assessing patients for entry in the trial [ie, central randomisation; sequentially numbered, opaque, sealed envelopes; sealed envelopes from a closed bag; numbered or coded bottles or containers; drugs prepared by the pharmacy; or other descriptions that contain elements convincing of concealment]); allocation not concealed (deemed to have not taken adequate measures to conceal allocation to study group assignments from those responsible for assessing patients for entry in the trial [ie, no concealment procedure was undertaken, sealed envelopes that were not opaque or were not sequentially numbered, or other descriptions that contained elements not convincing of concealment]); unclear allocation concealment (the authors did not report or provide a description of an allocation concealment approach that allowed for the classification as concealed or not concealed).

Confidence interval (CI):

quantifies the uncertainty in measurement; usually reported as 95% CI, which is the range of values within which we can be 95% sure that the true value for the whole population lies.

Constant comparison:1

a procedure used in qualitative research wherein newly collected data are compared in an ongoing fashion with data obtained earlier, to refine theoretically relevant categories.

Fixed effects model:2

gives a summary estimate of the magnitude of effect in meta-analysis. It takes into account within-study variation but not between-study variation and hence is usually not used if there is significant heterogeneity.

Grounded theory:1

an approach to collecting and analysing qualitative data with the aim of developing theories grounded in real world observations.

Inception cohort:

a defined, representative sample of patients is assembled for a study at a common (ideally early) point in their disease or condition and followed up over time.

Intention to treat analysis (ITT):

all patients are analysed in the groups to which they were randomised, even if they failed to complete the intervention or received the wrong intervention.

Number needed to harm (NNH):3

number of patients who, if they received the experimental treatment, would lead to 1 additional person being harmed compared with patients who receive the control treatment; this is calculated as 1/absolute risk increase (rounded to the next whole number), accompanied by the 95% confidence interval.

Number needed to treat (NNT):

number of patients who need to be treated to prevent 1 additional negative event (or to promote 1 additional positive event); this is calculated as 1/absolute risk reduction (rounded to the next whole number), accompanied by the 95% confidence interval.

Phenomenology:1

an approach to inquiry that emphasises the complexity of human experience and the need to understand that experience holistically as it is actually lived.

Quasi-randomised study:

participants are not randomly allocated to groups, but some other form of allocation is used (eg, day of the week, month of birth).

Relative benefit increase (RBI):

the proportional increase in the rates of good events between experimental and control participants; it is reported as a percentage (%).

Relative risk (RR) (risk ratio):

proportion of patients experiencing an outcome in the treated (or exposed) group divided by the proportion experiencing the outcome in the control (or unexposed) group.

Relative risk increase (RRI):

the proportional increase in bad outcomes between experimental and control participants; it is reported as a percentage (%).

Relative risk reduction (RRR):

the proportional reduction in bad outcomes between experimental and control participants; it is reported as a percentage (%).

Standardised mean difference:2

in a systematic review, a way of combining the results of studies that may have measured the outcome (eg, pain) in different ways, using different scales; effects are expressed as a standard value, with no units (difference between 2 means / estimate of within group standard deviation).

Symbolic interaction:1

a qualitative research method that focuses on the way in which people make sense of social interactions and the meanings they attach to social symbols such as language.

Theoretical sampling:1

in qualitative studies, selection of study participants based on emerging findings to ensure adequate representation of important themes.

Weighted:

statistical analysis accounts for differences in certain important variables.

Weighted mean difference:2

in a meta-analysis, used to combine outcomes measured on continuous scales (eg, height), assuming that all trials measured the outcome on the same scale; the mean, standard deviation and sample size of each group are known, and weight given to each trial is determined by the precision of its estimate of effect.

References

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