scholarly journals “Cross-sectional” stepped wedge designs always reduce the required sample size when there is no time effect

2017 ◽  
Vol 83 ◽  
pp. 108-109 ◽  
Author(s):  
Xin Zhou ◽  
Xiaomei Liao ◽  
Donna Spiegelman
Keyword(s):  
Sample Size ◽  
Time Effect ◽  
Stepped Wedge ◽  
Cross Sectional

scholarly journals A tutorial on sample size calculation for multiple-period cluster randomized parallel, cross-over and stepped-wedge trials using the Shiny CRT Calculator

2020 ◽  
Vol 49 (3) ◽  
pp. 979-995 ◽  
Author(s):  
Karla Hemming ◽  
Jessica Kasza ◽  
Richard Hooper ◽  
Andrew Forbes ◽  
Monica Taljaard
Keyword(s):  
Sample Size ◽  
Group Treatment ◽  
Single Point ◽  
Sample Size Calculation ◽  
Stepped Wedge ◽  
Cross Sectional ◽  
Multiple Observations ◽  
Sample Size Calculations ◽  
Correlation Structures ◽  
Cluster Randomized

Abstract It has long been recognized that sample size calculations for cluster randomized trials require consideration of the correlation between multiple observations within the same cluster. When measurements are taken at anything other than a single point in time, these correlations depend not only on the cluster but also on the time separation between measurements and additionally, on whether different participants (cross-sectional designs) or the same participants (cohort designs) are repeatedly measured. This is particularly relevant in trials with multiple periods of measurement, such as the cluster cross-over and stepped-wedge designs, but also to some degree in parallel designs. Several papers describing sample size methodology for these designs have been published, but this methodology might not be accessible to all researchers. In this article we provide a tutorial on sample size calculation for cluster randomized designs with particular emphasis on designs with multiple periods of measurement and provide a web-based tool, the Shiny CRT Calculator, to allow researchers to easily conduct these sample size calculations. We consider both cross-sectional and cohort designs and allow for a variety of assumed within-cluster correlation structures. We consider cluster heterogeneity in treatment effects (for designs where treatment is crossed with cluster), as well as individually randomized group-treatment trials with differential clustering between arms, for example designs where clustering arises from interventions being delivered in groups. The calculator will compute power or precision, as a function of cluster size or number of clusters, for a wide variety of designs and correlation structures. We illustrate the methodology and the flexibility of the Shiny CRT Calculator using a range of examples.

FAKTOR PENGETAHUAN YANG MEMPENGARUHI KETERATURAN IBU BALITA DALAM MENGUNJUNGI POSYANDU DI DESA CIPANGERAN KECAMATAN SAGULING KABUPATEN BANDUNG BARAT TAHUN 2017

2018 ◽  
Vol 5 (2) ◽  
pp. 13-20
Author(s):  
Lia Kamila ◽  
Liawati . ◽  
Suci Lailani Alipah
Keyword(s):  
Public Health ◽  
Data Collection ◽  
Sample Size ◽  
Health Center ◽  
Analytical Method ◽  
Random Sampling ◽  
Research Method ◽  
Cross Sectional ◽  
Public Health Center ◽  
Level Of Knowledge

ABSTRAK Indikator D/S di wilayah kerja Puskesmas Saguling Desa Cipangeran pada tahun 2016 menunjukkan masih rendahnya kunjungan balita dalam kegiatan posyandu dengan rata-rata hanya memcapai 41,5%, sedangkan target standar palayanan kota jumlah D/S yaitu 85%. Tujuan penelitian ini adalah untuk mengetahui keteraturan ibu dalam mengunjungi Posyandu dari faktor pengetahuan di Desa Cipangeran Kecamatan Saguling Kabupaten Bandung Barat tahun 2017. Metode penelitian ini menggunakan metode analitik dengan pendekatan cross sectional. Data yang digunakan adalah data primer. Populasi seluruh balita di wilayah kerja Puskesmas Saguling tahun 2016 sebanyak 424 ibu balita, besar sampel yang diambil 81 ibu balita, pengambilan sampel dengan menggunakan Sampel Random Sampling, pengumpulan data dengan hasil kuesioner berisi pertanyaan untuk mendapatkan data yang berkaitan dengan variabel yang diteliti. Hasil penelitian pengetahuan ibu balita didapatkan hampir setengah berada dikategori cukup yaitu 47 ibu balita (58%), namun masih ada ibu balita yang memiliki pengetahuan baik yaitu 18 ibu balita (22%), dan ibu balita yang memiliki pengetahuan kurang yaitu 16 ibu balita (20%). Kesimpulan dari penelitian didapatkan tingkat pengetahuan ibu balita yang tidak teratur dalam mengunjungi Posyandu di Desa Cipangeran Kecamatan Saguling Kabupaten Bandug Barat hampir setengah ibu balita berpengetahuan cukup. ABSTRACT The D / S indicator in the working area of ​​Saguling Public Health Center of Cipangeran Village in 2016 indicates that the low number of toddler visits in posyandu activities reaches an average of 41.5%, while the standard target for city / city is 85%. The purpose of this study is to determine the regularity of mothers in visiting Posyandu from knowledge factor in Cipangeran Village, Saguling District, West Bandung regency in 2017. This research method using analytical method with cross sectional approach. The data used is primary data.The population of all toddlers in the working area of Saguling Publich Health Center in 2016 were 424 mother, the sample size was 81 mother, using Random Sampling , data collection with questionnaires containing questions to obtain data related to the variables studied. The result of the research of the knowledge of the mother of the toddler is almost sufficient, namely 47 mothers (58%),but there are still mother who have good knowledge that is 18 mother of toddler (22%) and mother with less knowledge that is 16 mother of balita (20%). The conclusion of the research is the level of knowledge of irregular mother in visiting Posyandu in Cipangeran Village, Saguling, of West Bandung district, almost half of the toddler are knowledgeable enough.

scholarly journals Meal and Sleep Timing before and during the COVID-19 Pandemic: A Cross-Sectional Anonymous Survey Study from Sweden

2021 ◽  
Vol 3 (2) ◽  
pp. 251-258
Author(s):  
Christian Benedict ◽  
Luiz Eduardo Mateus Brandão ◽  
Ilona Merikanto ◽  
Markku Partinen ◽  
Bjørn Bjorvatn ◽  
...  
Keyword(s):  
Sample Size ◽  
Metabolic Health ◽  
Survey Study ◽  
Cross Sectional ◽  
Daily Routines ◽  
Sleep Timing ◽  
Social Jetlag ◽  
Meal Timing ◽  
At Home

The COVID-19 pandemic and related restrictions, such as stay-at-home-orders, have significantly altered daily routines and lifestyles. Given their importance for metabolic health, we herein compared sleep and meal timing parameters during vs. before the COVID-19 pandemic based on subjective recall, in an anonymous Swedish survey. Among 191 adults (mean age: 47 years; 77.5% females), we show that social jetlag, i.e., the mismatch in sleep midpoint between work and free days, was reduced by about 17 min during the pandemic compared with the pre-pandemic state (p < 0.001). Concomitantly, respondents’ sleep midpoint was shifted toward morning hours during workdays (p < 0.001). A later daily eating midpoint accompanied the shift in sleep timing (p = 0.001). This effect was mainly driven by a later scheduled first meal (p < 0.001). No difference in the timing of the day’s last meal was found (p = 0.814). Although our survey was limited in terms of sample size and by being cross-sectional, our results suggest that the delay in sleep timing due to the COVID-19 pandemic was accompanied by a corresponding shift in the timing of early but not late meals.

scholarly journals Feasibility of Race by Sex Intersectionality Research on Suicidality in the Adolescent Brain Cognitive Development (ABCD) Study

Children ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 437
Author(s):  
Shervin Assari ◽  
Shanika Boyce ◽  
Mohsen Bazargan
Keyword(s):  
Cognitive Development ◽  
Sample Size ◽  
Child Behavior Checklist ◽  
Reliability And Validity ◽  
Self Report ◽  
Large Sample Size ◽  
Cross Sectional ◽  
Cronbach Alpha ◽  
Rich Data ◽  
Suicidal Ideas

Intersectional research on childhood suicidality requires studies with a reliable and valid measure of suicidality, as well as a large sample size that shows some variability of suicidality across sex by race intersectional groups. Objectives: We aimed to investigate the feasibility of intersectionality research on childhood suicidality in the Adolescent Brain Cognitive Development (ABCD) study. We specifically explored the reliability and validity of the measure, sample size, and variability of suicidality across sex by race intersectional groups. Methods: We used cross-sectional data (wave 1) from the ABCD study, which sampled 9013 non-Hispanic white (NHW) or non-Hispanic black (NHB) children between the ages of 9 and 10 between years 2016 and 2018. Four intersectional groups were built based on race and sex: NHW males (n = 3554), NHW females (n = 3158), NHB males (n = 1164), and NHB females (n = 1137). Outcome measure was the count of suicidality symptoms, reflecting all positive history and symptoms of suicidal ideas, plans, and attempts. To validate our measure, we tested the correlation between our suicidality measure and depression and Child Behavior Checklist (CBCL) sub-scores. Cronbach alpha was calculated for reliability across each intersectional group. We also compared groups for suicidality. Results: We observed some suicidality history in observed 3.2% (n = 101) of NHW females, 4.9% (n = 175) of NHW males, 5.4% (n = 61) of NHB females, and 5.8% (n = 68) of NHB males. Our measure’s reliability was acceptable in all race by sex groups (Cronbach alpha higher than .70+ in all intersectional groups). Our measure was valid in all intersectional groups, documented by a positive correlation with depression and CBCL sub-scores. We could successfully model suicidality across sex by race groups, using multivariable models. Conclusion: Given the high sample size, reliability, and validity of the suicidality measure, variability of suicidality, it is feasible to investigate correlates of suicidality across race by sex intersections in the ABCD study. We also found evidence of higher suicidality in NHB than NHW children in the ABCD study. The ABCD rich data in domains of social context, self-report, schools, parenting, psychopathology, personality, and brain imaging provides a unique opportunity to study intersectional differences in neural circuits associated with youth suicidality.

Imaging and Cognitive Genetics: The Norwegian Cognitive NeuroGenetics Sample

2012 ◽  
Vol 15 (3) ◽  
pp. 442-452 ◽  
Author(s):  
Thomas Espeseth ◽  
Andrea Christoforou ◽  
Astri J. Lundervold ◽  
Vidar M. Steen ◽  
Stephanie Le Hellard ◽  
...  
Keyword(s):  
Sample Size ◽  
Cognitive Aging ◽  
Brain Function ◽  
Large Scale ◽  
Adult Life ◽  
Aging Brain ◽  
Adult Life Span ◽  
Cross Sectional ◽  
A Genome ◽  
Effects Of Aging

Data collection for the Norwegian Cognitive NeuroGenetics sample (NCNG) was initiated in 2003 with a research grant (to Ivar Reinvang) to study cognitive aging, brain function, and genetic risk factors. The original focus was on the effects of aging (from middle age and up) and candidate genes (e.g., APOE, CHRNA4) in cross-sectional and longitudinal designs, with the cognitive and MRI-based data primarily being used for this purpose. However, as the main topic of the project broadened from cognitive aging to imaging and cognitive genetics more generally, the sample size, age range of the participants, and scope of available phenotypes and genotypes, have developed beyond the initial project. In 2009, a genome-wide association (GWA) study was undertaken, and the NCNG proper was established to study the genetics of cognitive and brain function more comprehensively. The NCNG is now controlled by the NCNG Study Group, which consists of the present authors. Prominent features of the NCNG are the adult life-span coverage of healthy participants with high-dimensional imaging, and cognitive data from a genetically homogenous sample. Another unique property is the large-scale (sample size 300–700) use of experimental cognitive tasks focusing on attention and working memory. The NCNG data is now used in numerous ongoing GWA-based studies and has contributed to several international consortia on imaging and cognitive genetics. The objective of the following presentation is to give other researchers the information necessary to evaluate possible contributions from the NCNG to various multi-sample data analyses.

Various interdental aids, their effectiveness and recommendation; A Cross-Sectional Survey

2021 ◽  
Vol 15 (8) ◽  
pp. 2046-2049
Author(s):  
Ali Anwaar ◽  
Fareed Ahmad ◽  
Muhammad Shairaz Sadiq ◽  
Mustafa Qadeer ◽  
Muhammad Afzal ◽  
...  
Keyword(s):  
Sample Size ◽  
Oral Hygiene ◽  
Dental Hygiene ◽  
Study Data ◽  
Outpatient Department ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Know How ◽  
Medical College ◽  
The Masses

Objective: The aim of this study is to discover effectiveness of interdental aid, their use in the daily oral hygiene and suggestion of interdental aid to be used. Methods & Materials: This study was conducted among 503 convenient samples of patients from outpatient department of IOD, CMH Lahore medical college. It is a questionnaire-based study. Data collected from February 2021 to April 2021. A written consent was taken. All the examiners were calibrated for check-up and questionnaire was filled on effectiveness of interdental aids and its uses and recommendation by individual. Results: Total 503 people with 230 females and 273 males were participated in the study. Majority of the sample size did not know how to do interdental cleaning. Also, there is lack of awareness about dental hygiene in the masses. Conclusion: Amongst the patients which came for their dental treatments who were using any interdental cleaning aid, toothpick was the most common choice. However, toothpicks are not a recommended aid because it can damage the gums and cause bleeding. Awareness should be given to the patients so that they use appropriate methods and aids for interdental cleaning. Keywords: Interdental Aids, Effectiveness

scholarly journals Pattern of occlusal contacts in intercuspal position of natural teeth

2016 ◽  
Vol 4 (1) ◽  
pp. 19
Author(s):  
Tanzeela Imran ◽  
Naseer Ahmed ◽  
Bushra Nazeer
Keyword(s):  
Sample Size ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Posterior Teeth ◽  
Contact Areas ◽  
Natural Teeth ◽  
Centric Occlusion

The purpose of this study was to determine the patterns of occlusal contacts and location in intercuspal position of natural teeth.A cross-sectional study was conducted with a sample size of around seventy patients within a span of seven months, complete mouth impressions were made of each patient with hydrocolloid material and the impressions were poured in dental stone. The contact areas of the teeth in the maximum intercuspation position were determined by wax. Three distinct types of indentations were noted on the wax interocclusal record. Then similarly the centric occlusion contacts of the teeth on the cast were determined by interposing a new piece of wax, approximating the casts in the maximum intercuspation position by hand, and applying pressure. The oral and cast wax recordings were then compared. The occlusal relation for each individual tooth was then classified and recorded in a Performa.Following wax interocclusal record of natural teeth in intercuspation an ideal occlusion was absent, a difference in morphology of anterior and posterior teeth was also evident that inevitably affects the nature of occlusal contacts.The ideal occlusion was not found in any of the patient’s investigation.

scholarly journals The prevalence of sleep disturbances among physicians and nurses facing the COVID-19 patients: a systematic review and meta-analysis

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Nader Salari ◽  
Habibolah Khazaie ◽  
Amin Hosseinian-Far ◽  
Hooman Ghasemi ◽  
Masoud Mohammadi ◽  
...  
Keyword(s):  
Systematic Review ◽  
Sample Size ◽  
Medical Staff ◽  
Sleep Disturbances ◽  
Meta Analysis ◽  
Workplace Stress ◽  
Cross Sectional ◽  
Significance Level ◽  
Nurses And Physicians ◽  
As Stress

Abstract Background In all epidemics, healthcare staff are at the centre of risks and damages caused by pathogens. Today, nurses and physicians are faced with unprecedented work pressures in the face of the COVID-19 pandemic, resulting in several psychological disorders such as stress, anxiety and sleep disturbances. The aim of this study is to investigate the prevalence of sleep disturbances in hospital nurses and physicians facing the COVID-19 patients. Method A systematic review and metanalysis was conducted in accordance with the PRISMA criteria. The PubMed, Scopus, Science direct, Web of science, CINHAL, Medline, and Google Scholar databases were searched with no lower time-limt and until 24 June 2020. The heterogeneity of the studies was measured using I2 test and the publication bias was assessed by the Egger’s test at the significance level of 0.05. Results The I2 test was used to evaluate the heterogeneity of the selected studies, based on the results of I2 test, the prevalence of sleep disturbances in nurses and physicians is I2: 97.4% and I2: 97.3% respectively. After following the systematic review processes, 7 cross-sectional studies were selected for meta-analysis. Six studies with the sample size of 3745 nurses were examined in and the prevalence of sleep disturbances was approximated to be 34.8% (95% CI: 24.8-46.4%). The prevalence of sleep disturbances in physicians was also measured in 5 studies with the sample size of 2123 physicians. According to the results, the prevalence of sleep disturbances in physicians caring for the COVID-19 patients was reported to be 41.6% (95% CI: 27.7-57%). Conclusion Healthcare workers, as the front line of the fight against COVID-19, are more vulnerable to the harmful effects of this disease than other groups in society. Increasing workplace stress increases sleep disturbances in the medical staff, especially nurses and physicians. In other words, increased stress due to the exposure to COVID-19 increases the prevalence of sleep disturbances in nurses and physicians. Therefore, it is important for health policymakers to provide solutions and interventions to reduce the workplace stress and pressures on medical staff.

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