scholarly journals Learning from Cochrane systematic reviews: what improvements do these suggest for the design of trials?

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 178
Author(s):  
Stefania Pirosca ◽  
Mike Clarke ◽  
Shaun Treweek
Keyword(s):  
Sample Size ◽  
Systematic Reviews ◽  
Future Research ◽  
Randomised Trials ◽  
Review Group ◽  
The Central Nervous System ◽  
System Review ◽  
Larger Sample ◽  
Do So

Background: Many randomised trials have serious methodological flaws that fatally undermine their results, which makes the research wasteful. This is of concern for many, including those doing systematic reviews that include trials. Cochrane systematic reviews have a section called ‘ Implications for research’, which allows authors of the review to present their conclusions on how future research might be improved. Looking at these conclusions might highlight priority areas for improvement. Methods: We focused on the Cochrane Schizophrenia Review Group and the Multiple sclerosis and rare diseases of the central nervous system Review Group (the MS Review Group).  Reviews with citation dates between 2009 and 2019 were identified and the recommendations of review authors in ‘ Implications for research’ were put into categories. Results: Between 2009 and 2019 we identified 162 reviews for the Schizophrenia Review Group and 43 reviews for the MS Review Group. We created 22 categories of recommendations in total, of which 12 were common to both groups. The five most used categories were the same for both: better choice of outcomes; better choice of intervention/comparator; longer follow-up; larger sample size; use of validated scales.  Better choice of outcomes and/or intervention/comparator was recommended in over 50% of reviews. Longer follow-up and larger sample size were recommended in over a third, with use of validated scales being suggested in around a fifth of reviews. There was no obvious pattern of improvement over time for trials included in systematic reviews published by both groups. Conclusions: We suggest that trialists working in these and other areas ask themselves, or are compelled to do so by others (e.g. funders), why they have chosen their outcomes, intervention and comparator, whether follow-up is long enough, if the sample size is big enough and whether the scales they choose to measure their outcomes are appropriate.

scholarly journals What improvements do Cochrane systematic reviewers suggest for the design of trials?

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 178
Author(s):  
Stefania Pirosca ◽  
Mike Clarke ◽  
Shaun Treweek
Keyword(s):  
Sample Size ◽  
Systematic Reviews ◽  
Future Research ◽  
Randomised Trials ◽  
Review Group ◽  
The Central Nervous System ◽  
System Review ◽  
Larger Sample ◽  
Over Time

Background: Many randomised trials have serious methodological flaws that fatally undermine their results, which makes the research wasteful. This is of concern for many, including those doing systematic reviews that include trials. Cochrane systematic reviews all have a section called ‘Implications for research’, which allows authors of the review to present their conclusions on how future research might be improved. Looking at these conclusions might highlight priority areas for improvement. Methods: We focused on the Cochrane Schizophrenia Review Group and the Multiple sclerosis and rare diseases of the central nervous system Review Group (the MS Review Group).  Reviews with citations between 2009 and 2019 were identified and the recommendations given by review authors in ‘Implications for research’ were put into categories. Results: Between 2009 and 2019 we identified 162 reviews for the Schizophrenia Review Group and 43 reviews for the MS Review Group. We created 22 categories in total, of which 12 were common to both groups. The five most used categories were the same for both: better choice of outcomes; better choice of intervention/comparator; longer follow-up; larger sample size; use of validated scales.  Better choice of outcomes and/or intervention/comparator was recommended in over 50% of reviews. Longer follow-up and larger sample size were recommended in over a third, with use of validated scales being suggested in around a fifth of reviews. There was no obvious pattern of improvement over time for trials included in systematic reviews published by both groups. Conclusions: We suggest that trialists working in these areas (and others too) ask themselves why they have chosen their particular outcomes, intervention and comparator, whether follow-up is long enough, if the sample size is big enough and whether the scales  they choose to measure their outcomes are appropriate.

A Longitudinal Field Investigation of Auditor Risk Assessments and Sample Size Decisions

2003 ◽  
Vol 78 (4) ◽  
pp. 983-1002 ◽  
Author(s):  
Randal J. Elder ◽  
Robert D. Allen
Keyword(s):  
Sample Size ◽  
Field Investigation ◽  
Risk Assessments ◽  
Sample Sizes ◽  
Accounting Firms ◽  
Inherent Risk ◽  
Changes In Risk ◽  
Larger Sample ◽  
Average Sample ◽  
Do So

This study examines changes in auditor risk assessments and sample size decisions based on information gathered from three large accounting firms for audits during 1994 and 1999. The five-year interval between data collection periods allows us to measure changes in risk assessments and sample sizes between the two periods. Auditors relied on controls and assessed inherent risk below the maximum on most audits, and were more likely to do so in the later period, consistent with a trend of lower risk assessment levels. Average sample sizes declined between 1994 and 1999 for the firms that had larger sample sizes in the earlier period. Overall, we find a significant relationship between inherent risk assessments and sample sizes, but this relationship is stronger in the earlier period and is not significant for all firms, especially in the later period. We find limited evidence of a relationship between control risk and sample sizes.

Sounds Affecting the Moments of Stuttering in Multilingualism: A Case Study

2016 ◽  
Vol 38 (3) ◽  
pp. 154-160 ◽  
Author(s):  
Taryn Morrish ◽  
Amy Nesbitt ◽  
Mia le Roux ◽  
Ursula Zsilavecz ◽  
Jeannie van der Linde
Keyword(s):  
Sample Size ◽  
Language Proficiency ◽  
Mixed Method ◽  
Interrater Reliability ◽  
Future Research ◽  
African Language ◽  
Mixed Method Design ◽  
Larger Sample

Research involving stuttering in multilingual individuals is limited. Speech-language therapists face the challenge of treating a diverse client base, which includes multilingual individuals. The aim of this study was to examine the stuttering moments across English, Afrikaans, and German in a multilingual speaker. A single multilingual adult with a severe developmental stutter participated in this study. A mixed-method design was implemented. The results were perceptually analyzed, and interrater reliability was determined. The results revealed that the voiceless plosive [k], the voiceless fricative [f], and the plosive-lateral approximant cluster [kl] caused stuttering moments across the languages. More stuttering moments occurred on consonants as opposed to vowels. The most prominent core behavior was prolongations. Language proficiency plays a role in the increase of the moments of stuttering in the least proficient language. Future research on a larger sample size is recommended. Research on African language speaking multilingual person who stutters (PWS) should be pursued.

Short Implants in Maxillary and Mandibular Rehabilitations: Interim Results (6 to 42 Months) of a Prospective Study

2015 ◽  
Vol 41 (1) ◽  
pp. 50-55 ◽  
Author(s):  
Silvio Taschieri ◽  
Stefano Corbella ◽  
Raffaella Molinari ◽  
Massimo Saita ◽  
Massimo Del Fabbro
Keyword(s):  
Sample Size ◽  
Cumulative Survival ◽  
Short Implants ◽  
Significant Difference ◽  
Upper Jaw ◽  
Maxilla And Mandible ◽  
A Prospective Study ◽  
Bone Height ◽  
Larger Sample

The aim of this single-cohort study was to evaluate clinical survival and success of partial rehabilitation supported by reduced-length implants in maxilla and mandible. Data from 53 short implants placed in 41 patients are presented. Before surgery mean residual bone height was 6.21 ± 1.05 mm in the upper jaw and 10.73 ± 1.63 mm in the mandible. None of the implants failed, and the cumulative survival rate was 100% at 1 year after prosthetic loading. Mean peri-implant bone loss was 0.69 ± 0.24 mm for maxillary implants and 0.73 ± 0.23 mm for mandibular implants, and there was no significant difference between the 2 jaws. No complications were recorded. Despite the limitations of this study concerning study design and sample size, short implants may be considered effective in supporting partial rehabilitation in both maxilla and mandible. More well-designed studies with a larger sample size and longer follow-up are needed to validate the use of short implants.

scholarly journals COVID-19: underpowered randomised trials, or no randomised trials?

Trials ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Atle Fretheim
Keyword(s):  
Public Health ◽  
Sample Size ◽  
Systematic Reviews ◽  
Sample Size Calculation ◽  
Scientific Progress ◽  
Face Mask ◽  
Health Interventions ◽  
Randomised Trials ◽  
Public Health Interventions ◽  
Key Barrier

AbstractA recently published trial of face mask use to protect against COVID-19 demonstrated a key barrier to carrying out randomised trials in public health: the need for unattainably large sample sizes. For many public health interventions, the choice is not between sufficiently powered trials and underpowered trials, but between underpowered trials and no trials at all. Underpowered trials should be viewed as contributions to the larger body of evidence, alongside other studies of various sizes and designs, collectively assessed and synthesized in systematic reviews. Overemphasis on sample size calculation is probably more of a hindrance than a help to scientific progress.

A CONTINUED STUDY TO DERTERMINE THE ASSOCIATION BETWEEN CHRONIC KIDNEY DISEASE AND NON-ALCOHALIC FATTY LIVER DISEASE AND ITS EFFECT ON eGFR

2021 ◽  
pp. 133-136
Author(s):  
Arvind Gupta ◽  
Poonam Gupta ◽  
Anubha Srivastava ◽  
Amit Kumar Panday
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Physical Examination ◽  
Sample Size ◽  
Care Center ◽  
Tertiary Care ◽  
Ckd Stage ◽  
High Prevalence ◽  
Larger Sample

Background: The present study was conduct in Motilal Nehru Medical College, Swaroop Rani Nehru Hospital Prayagraj, a tertiary care center and data was collected over a period from January 2019 to April 2020. All 78 patients of CKD attending OPD & IPD of General Medicine and Nephrology, diagnosed by suggestive symptoms and conrmed by physical examination and laboratory investigations were taken , Among the subjects, those having NAFLD were grouped as cases. Patients of Chronic Kidney disease not having NAFLD were grouped as controls. Aim & Objective: To study the prevalence of NAFLD in patients of CKD and establish the association between NAFLD and CKD by studying the effect of NAFLD on eGFR. Methodology: This was a 16 month case control study. Total 78 patients with age 18-65 years , Either sex with Chronic kidney disease diagnosed by USG, KFT, physical examination and having NAFLD Patients with known diagnosis of metabolic syndrome, diabetes and/or hypothyroidism. Those on hepatotoxic medication (amiodarone, barbiturates, glucocorticoids, etc.). The data so collected was entered into computer using Microsoft Excel 2013 software and was subjected to statistical analysis. Result : The ndings of present study thus reafrm the observations of previous studies that highlight a high prevalence of NAFLD in CKD patients and link it to the deranged metabolic factors. In present study we could not found a convincing evidence supporting a relationship between NAFLD and its severity with progression of CKD, probably owing to three major factors – rst, owing to Discussion 71 limitation of study population in only CKD stage 3 and secondly, owing to absence of retrospective data tracing the time of development of NAFLD in these patients and thirdly, inability to carry out long-time follow-up of patients. In present study, though minor changes in eGFR values in patients were seen, however, during the limited period of follow-up no shift from Stage 3 to other stages of CKD was observed. All the patients were regular in follow-up and had a good medical compliance and in general did not show a phenomenal deterioration in renal function within the short span of study. Keeping in view these limitations, further studies are recommended on a larger sample size with inclusion of patients from different stages of CKD spanning over a longer duration of follow-up to see whether NAFLD presence and its severity has a relationship with long-term progression of CKD. Conclusion: The present study showed that, CKD patients had a high prevalence of NAFLD. The ndings also show that FIB-4 scores are useful noninvasive methods for detection of NAFLD in CKD patients. The ndings showed a possible signicant association between NAFLD and lower eGFR rates. One of the limitations of the present study was presence of only Stage 3 CKD patients, owing to which the linear correlations between eGFR and NAFLD severity could not be assessed properly. Further studies on larger sample size with inclusion of patients with other CKD stages too are recommended.

scholarly journals Replication and contradiction of highly cited research papers in psychiatry: 10-year follow-up

2015 ◽  
Vol 207 (4) ◽  
pp. 357-362 ◽  
Author(s):  
Aran Tajika ◽  
Yusuke Ogawa ◽  
Nozomi Takeshima ◽  
Yu Hayasaka ◽  
Toshi A. Furukawa
Keyword(s):  
Sample Size ◽  
Small Sample Size ◽  
Total Sample ◽  
Small Sample ◽  
Research Papers ◽  
Effective Interventions ◽  
Mean Differences ◽  
Larger Sample ◽  
Highly Cited

BackgroundContradictions and initial overestimates are not unusual among highly cited studies. However, this issue has not been researched in psychiatry.AimsTo assess how highly cited studies in psychiatry are replicated by subsequent studies.MethodWe selected highly cited studies claiming effective psychiatric treatments in the years 2000 through 2002. For each of these studies we searched for subsequent studies with a better-controlled design, or with a similar design but a larger sample.ResultsAmong 83 articles recommending effective interventions, 40 had not been subject to any attempt at replication, 16 were contradicted, 11 were found to have substantially smaller effects and only 16 were replicated. The standardised mean differences of the initial studies were overestimated by 132%. Studies with a total sample size of 100 or more tended to produce replicable results.ConclusionsCaution is needed when a study with a small sample size reports a large effect.

Thin Layer Chromatographic Test for Mammalian Urine on Wheat

1973 ◽  
Vol 56 (3) ◽  
pp. 637-639
Author(s):  
Joel J Thrasher
Keyword(s):  
Thin Layer ◽  
Sample Size ◽  
Experimental Work ◽  
Collaborative Study ◽  
Detection Level ◽  
Soxhlet Extractor ◽  
Modified Method ◽  
Minimum Detection Level ◽  
Larger Sample

Abstract Follow-up experimental work of the 1971 preliminary method study revealed the need for a change in sample size, an improved extract cleanup technique, and the identification of a urine-specific metabolite. A modified method collaboratively tested in 1972 is capable of handling a larger sample in the Soxhlet extractor. The extract is cleaned of interfering substances by chromatography with an appropriate solvent prior to 2-dimensional TLC. The indicator metabolites, urea, allantoin, and indican, are detected by sequential sprays. The collaborative study resulted in 90% correct positive determinations with no false positives. The minimum detection level is approximately 2 μl urine/9 g wheat. The method has been adopted as official first action.

An evaluation of used objects in bank TV commercials in Ramadan

2019 ◽  
Vol 10 (4) ◽  
pp. 1219-1229 ◽  
Author(s):  
Oguzhan Aydin ◽  
Selcuk Burak Hasiloglu
Keyword(s):  
Sample Size ◽  
Future Research ◽  
Muslim Country ◽  
Content Type ◽  
Research Findings ◽  
Fuzzy Logic Method ◽  
Tv Commercials ◽  
Religious Objects ◽  
The Impact ◽  
Larger Sample

Purpose The purpose of this study is to find the most effective objects used in Ramadan TV ads of banks operated in Turkey and to determine superiority of the objects among these ads. Design/methodology/approach This research examines used objects in bank TV advertisements for the month of Ramadan by applying content analysis and fuzzy logic method. Findings The most prominent of the findings, as a result of the research, are kids and the elder objects in bank TV commercials. The research findings also reveal the importance of religious objects of Ramadan ads. Research limitations/implications The limitation of this research is non-generalization of the results because of sample size. Future research could explore the impact of objects used in TV ads on consumers with a larger sample size. Practical implications The banks are eager to look for opportunities by launching campaigns during the period of Ramadan. Special occasions such as religious holidays are seen as a new market that should not to be missed by the finance sector, and therefore, the number of bank TV commercials increase dramatically in this term. However, it is important for banks to know which objects are more effective. In this study, it is revealed that objects used in TV ads are more effective. Originality/value This is the first study to examine bank TV commercials during the period of Ramadan. It is also important to reflect Turkish consumers’ perspective and banks’ promotion activities in a Muslim country.

scholarly journals Prospective Randomized Study Comparing Concomitant Chemoradiotherapy Using Three Weekly Cisplatin and Biweekly 5-Fluorouracil versus Weekly Paclitaxel in Locally Advanced Carcinoma Cervix

2018 ◽  
Vol 04 (02) ◽  
pp. 054-060
Author(s):  
Sapna Marcus ◽  
Jasmeet Kaur ◽  
Hanuman Yadav
Keyword(s):  
Overall Survival ◽  
Sample Size ◽  
Concurrent Chemoradiotherapy ◽  
Randomized Study ◽  
Locally Advanced ◽  
Unmet Need ◽  
Carcinoma Cervix ◽  
Larger Sample ◽  
Populous Country

AbstractIndia being the second most populous country in the world accounted for 25% of cervical cancer death according to GLOBOCAN 2012. Although there are many agents available, the need for a model chemotherapy regimen that is effective and at the same time less toxic and has easy affordability is the current unmet need. We devised a study with the most commonly available and affordable drugs such as Cisplatin, 5-Fluorouracil (5FU), and Paclitaxel. The main objective was to study the efficacy of concurrent chemoradiotherapy in treatment of carcinoma cervix, using two different regimens in terms of clinical response evidenced clinically as well as on imaging. Secondary objectives were to assess the progression-free and overall survival. It was clearly evident that the response rate could be appreciated clinically in arm B over A; however, this difference could not be justified by statistical methods. Toxicities observed in both the arms was comparable, and in terms of progression-free and overall survival, the differences were not significant suggesting that the both the options could be considered in the treatment. Although the outcome looks promising prompting exploration of more such combinations that are easily available in the rural hospitals, but because of smaller sample size and smaller follow-up, a multi-institutional study with a larger sample size and a longer follow-up is definitely required to set the ball rolling in favor of combination chemotherapy, including cisplatin and 5FU.

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