Article Text
PDF
Statistics from Altmetric.com
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.
Conversation analysis:1
examines the organization and structure of conversation, including all that is said.
Crossover trial:
a method of comparing 2 interventions in which patients are switched to the alternative intervention after a specified period of time.
Data saturation (saturation, redundancy):2
process of collecting data in a qualitative research study to the point where no new themes are generated.
Ethnography (ethnographic study):2
an approach to inquiry that focuses on the culture or subculture of a group of people, with an effort to understand the world view of those under study.
Ethnomethodology:
an approach to inquiry that focuses on the way people make sense of their everyday lives.
Grounded theory:2
an approach to collecting and analysing qualitative data with the aim of developing theories grounded in real world observations.
Hazard ratio:3
the weighted relative risk over the entire study period; often reported in the context of survival analysis.
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.
Nested case control study:
a case control study done within a prospective cohort study.
Nominal group technique:4
a highly structured group process that provides an orderly procedure for obtaining qualitative information from specific groups who are closely associated with the area of interest.
Number needed to harm (NNH):5
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.
Power:6
the ability of a study to detect an actual effect or difference between groups; it has to do with the adequacy of sample size. Before a study begins, researchers often calculate the number of participants required to detect a difference between 2 groups. If a study has insufficient power (ie, sample size is too small), actual differences between groups may not be detected.
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 (%).
Receiver operating characteristic (ROC) curve:7
an analysis used to assess the clinical usefulness of a diagnostic or screening test. It yields a score that has the highest rates of both sensitivity and specificity with respect to a diagnosis – that is, a score that will give the maximum rate of accurate classifications.
Standardised mean difference:8
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).
Weighted mean difference:8
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.