Evidence map›Paper›PMID 14586662›Full record

Trial reportLangenbeck's archives of surgery2004

Checking for interviewer bias in outcome assessment: a method for strengthening the design of prospective, randomised trials in surgery.

M Koller, S Hoffmann, M Rothmund, W Lorenz, U Plaul

Abstract readClinical TrialRandomized Controlled Trial
PubMed Publisher
In one paragraph

Trial report in Langenbeck's archives of surgery, 2004. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Article
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors.

M KollerInstitute of Theoretical Surgery, Philipps-University Marburg, Baldingerstrasse, 35033 Marburg, Germany. koller@mailer.uni-marburg.de
S Hoffmann
M Rothmund
W Lorenz
U Plaul

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundBlind, randomised trials are conceived as the gold standard in clinical research, but this ideal, in its strict sense, can rarely be achieved in surgical settings. One way to strengthen the study design is to check for observer bias in the assessment and evaluation of surgical outcome.

methodIn a randomised, prospective trial comparing nasogastric versus gastrostomy tubes the primary endpoint was the subjective inconvenience induced by the tube system and was assessed in the context of a standardised face-to-face interview. These interviews were tape-recorded on a pocket memo. Two independent raters listened to these interviews and judged--on the basis of how the interviewer formulated the questions--which treatment arm they thought the patients were assigned to and how confident they were in their judgement.

resultsThe overall proportion of correct judgements was 50.5% for rater 1 and 53.2% for rater 2. In other words, both judgement performances were not greater than chance. Nevertheless, the raters' confidence in their judgements increased significantly ( P<0.05) in the course of the rating procedure, whereas the actual proportion of correct judgements did not. There was no overlap between the two raters [kappa = 0.022, not significant (NS)] and between actual group assignment and both raters' judgements (kappa = 0.012, NS and kappa = 0.110, NS).

conclusionThe two independent raters were not able to detect systematic variations in the interviewing style that were contingent on treatment arm assignment. This gives further credence to the results of the randomised trial showing greater patient-reported discomfort and inconvenience with the nasogastric tube than with the gastrostomy tube. The present report describes a feasible method to monitor subtle biases that may occur in trial settings. This helps to strengthen the design of randomised clinical trials in surgery.

Indexed as

Observer VariationFeasibility StudiesGastrostomyHumansIntubation, GastrointestinalOutcome Assessment, Health CareProspective StudiesRandomized Controlled Trials as Topic

Identifiers

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.