‘Randomisation bias’ in the medical literature: a review

Sianesi, Barbara

doi:10.1920/wp.ifs.2016.1623

Cited by 3 publications

(2 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When there is no relationship between attrition and exposure or outcome variables, attrition can be managed by increasing sample size; however, when this relationship is statistically significant, results are biased and conclusions may be erroneous. [7]…”

Section: Discussionmentioning

confidence: 99%

“…Randomized controlled trials (RCTs) are the most rigorous type of clinical trials and the best method for assessing causal relationships. [7] The unique characteristics of RCTs are the use of an intervention in an intervention group, inclusion of a control group, and the use of random allocation. [8] Despite the rigorousness and usefulness of RCTs, they are always prone to some types of errors.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Bias in clinical trials into the effects of complementary and alternative medicine therapies on hemodialysis patients

Adib-Hajbaghery

Nabizadeh-Gharghozar

Nasirpour

2019

J Family Med Prim Care

View full text Add to dashboard Cite

Background: Chronic renal failure is among the major health challenges in the world. Many clinical trials have been conducted to assess the effects of complementary and alternative therapies on hemodialysis-related outcomes. However, a number of biases may affect the results of these studies. Aims: This study aimed to assess biases in randomized clinical trials into the effects of complementary and alternative therapies on hemodialysis patients. Settings and Design: A critical review on clinical trials into the effects of complementary and alternative therapies therapies on hemodialysis patients. Materials and Methods: This study was conducted on 114 randomized clinical trials which had been published in 2012–2017 into the effects of complementary and alternative therapies on hemodialysis patients. The Cochrane Risk of Bias Tool was employed to assess biases in the included trials. The collected data were presented using the measures of descriptive statistics, namely absolute and relative frequencies. Results: Among 114 included trials, 71.05% (81 trials) had used low bias methods for random sequence generation, while 60.52% (69 trials) had provided no clear information about allocation concealment. Moreover, respecting blinding, 57.89% of trials (66 trials) were low bias. Around 60.52% of trials (69 trials) had no attrition between randomization and final follow-up assessment and 84.21% (96 trials) had apparently reported all intended outcomes. Conclusions: This study shows that 50% of randomized clinical trials into the effects of complementary and alternative therapies on hemodialysis patients have low bias. Yet, quality improvement is still needed to produce more conclusive evidence.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bias in clinical trials into the effects of complementary and alternative medicine therapies on hemodialysis patients

Adib-Hajbaghery

Nabizadeh-Gharghozar

Nasirpour

2019

J Family Med Prim Care

View full text Add to dashboard Cite

show abstract

A Critical Introduction to Instrumental Variables for Sibship Size Based on Twin Births

Öberg

2019

Cliometrics of the Family

View full text Add to dashboard Cite

Evidence of randomisation bias in a large-scale social experiment: The case of ERA

Sianesi

2017

Journal of Econometrics

View full text Add to dashboard Cite

One of the most powerful critiques of the use of randomised experiments in the social sciences is the possibility that individuals might react to the randomisation itself, thereby rendering the causal inference from the experiment irrelevant for policy purposes. In this paper we set out a theoretical framework for the systematic consideration of "randomisation bias", and provide what is to our knowledge the first empirical evidence on this form of bias in an actual social experiment, the UK Employment Retention and Advancement (ERA) study. Specifically, we empirically test the extent to which random assignment has affected the process of participation in the ERA study. We further propose a non-experimental way of assessing the extent to which the treatment effects stemming from the experimental sample are representative of the impacts that would have been experienced by the population who would have been exposed to the program in routine mode. We consider both the case of administrative outcome measures available for the entire relevant sample and of survey-based outcome measures. For the case of survey outcomes we extend our estimators to also account for selective non-response based on observed characteristics. Both for the case of administrative and survey data we further extend our proposed estimators to deal with the non-linear case of binary outcomes. JEL codes: C21, J18, J38

show abstract

‘Randomisation bias’ in the medical literature: a review

Cited by 3 publications

References 39 publications

Bias in clinical trials into the effects of complementary and alternative medicine therapies on hemodialysis patients

Bias in clinical trials into the effects of complementary and alternative medicine therapies on hemodialysis patients

A Critical Introduction to Instrumental Variables for Sibship Size Based on Twin Births

Evidence of randomisation bias in a large-scale social experiment: The case of ERA

Contact Info

Product

Resources

About