scholarly journals A combination sampling approach for epidemiologic research in humanitarian settings: a case analysis of a study of depressive disorder prevalence among refugees in Greece

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Danielle N. Poole ◽  
Nathaniel A. Raymond ◽  
Jos Berens ◽  
Mark Latonero ◽  
Julie Ricard ◽  
...  
Keyword(s):  
Depressive Disorder ◽  
Case Analysis ◽  
Refugee Camp ◽  
Second Phase ◽  
Two Phase ◽  
Humanitarian Emergencies ◽  
Prevention And Treatment ◽  
Phase Sampling ◽  
Two Phase Sampling ◽  
Sampling Approach

Abstract Background Understanding the burden of common mental health disorders, such as depressive disorder, is the first step in strengthening prevention and treatment in humanitarian emergencies. However, simple random sampling methods may lead to a high risk of coercion in settings characterized by a lack of distinction between researchers and aid organizations, mistrust, privacy concerns, and the overarching power differential between researchers and populations affected by crises. This case analysis describes a sampling approach developed for a survey study of depressive disorder in a Syrian refugee camp in Greece (n = 135). Discussion Syrian refugees face an extraordinarily high burden of depressive disorder during the asylum process (43%), necessitating population screening, prevention, and treatment. In order to preserve the informed consent process in this refugee camp setting, the research team developed a two-phase sampling strategy using a map depicting the geographical layout of the housing units within the camp. In the first phase, camp management announced a research study was being undertaken and individuals were invited to volunteer to participate. The participants’ container (housing) numbers were recorded on the map, but were not linked to the survey data. Then, in the second phase, the camp map was used for complementary sampling to reach a sample sufficient for statistical analysis. As a result of the two phases of the sampling exercise, all eligible adults from half the containers in each block were recruited, producing a systematic, age- and sex-representative sample. Conclusions Combining sampling procedures in humanitarian emergencies can reduce the risk of coerced consent and bias by allowing participants to approach researchers in the first phase, with a second phase of sampling conducted to recruit a systematic sample. This case analysis illuminates the feasibility of a two-phase sampling approach for drawing a quasi-random, representative sample in a refugee camp setting.

New regression estimators in forest inventories with two-phase sampling and partially exhaustive information: a design-based Monte Carlo approach with applications to small-area estimation

2013 ◽  
Vol 43 (11) ◽  
pp. 1023-1031 ◽  
Author(s):  
Daniel Mandallaz ◽  
Jochen Breschan ◽  
Andreas Hill
Keyword(s):  
Auxiliary Information ◽  
Cluster Sampling ◽  
Lidar Data ◽  
Second Phase ◽  
Regression Estimator ◽  
Two Phase ◽  
Sampling Schemes ◽  
Forest Inventories ◽  
Phase Sampling ◽  
Two Phase Sampling

We consider two-phase sampling schemes where one component of the auxiliary information is known in every point (“wall-to-wall”) and a second component is available only in the large sample of the first phase, whereas the second phase yields a subsample with the terrestrial inventory. This setup is of growing interest in forest inventory thanks to the recent advances in remote sensing, in particular, the availability of LiDAR data. We propose a new two-phase regression estimator for global and local estimation and derive its asymptotic design-based variance. The new estimator performs better than the classical regression estimator. Furthermore, it can be generalized to cluster sampling and two-stage tree sampling within plots. Simulations and a case study with LiDAR data illustrate the theory.

Depression in Patients with Schizophrenia in a Psychiatry Hospital in Lagos, Nigeria

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Akinjola O ◽  
◽  
Lawal RA ◽  
Ojo AM ◽  
Adeosun II ◽  
...  
Keyword(s):  
Social Support ◽  
Depressive Symptoms ◽  
Depressive Disorder ◽  
Second Phase ◽  
Two Phase ◽  
Good Treatment Outcome ◽  
Phase Study ◽  
Poor Social Support ◽  
Schizophrenic Patients

Schizophrenia is a devastating and highly disabling disorder associated with long-term consequences. Treatment is often made difficult by the presence of comorbidities like depression which when considered in management ensures good outcome. This study aimed to determine the prevalence and correlates of depression in schizophrenia. It is a two-phase study involving 320 outpatients recruited by consecutive sampling. The first phase entails confirming diagnosis with Mini International Neuropsychiatric Interview (MINI), psychotic disorder module, assessing socio-demographic characteristic and screening for depressive symptoms with the Beck Depression Inventory (BDI) by a trained assistant. In the second phase, the researcher then assesses for depressive disorder using MINI, depressive disorder module among subjects who screened positive with BDI together with 10% of those who screened negative. Over four-fifth (83.4%) of the participants were less than 50 years, they were mostly females (57.2%), of Yoruba ethnic group (59.7%), Christians (75.6%), and earn below ₦18,000 monthly or nothing (72.2%). Also, a large proportion (86.2%) had good social support. Over a third of the participants were married (38.1%) with about four-fifth of these living with their spouses. The prevalence of depressive symptoms and depressive disorder were 49.7% and 38.4% respectively. Logistic regression revealed that poor social support predicts depressive in Schizophrenia. In conclusion, Depression is common in patients with schizophrenia. Therefore, thorough evaluation of schizophrenic patients is necessary so that, co-morbid depression when present can be detected and considered in management to ensure good treatment outcome.

scholarly journals Response-dependent two-phase sampling designs for biomarker studies

2014 ◽  
Vol 42 (2) ◽  
pp. 268-284 ◽  
Author(s):  
Michael A. McIsaac ◽  
Richard J. Cook
Keyword(s):  
Two Phase ◽  
Phase Sampling ◽  
Two Phase Sampling

Sample size allocation in two-phase sampling

1974 ◽  
Vol 3 (11) ◽  
pp. 1025-1040
Author(s):  
J. Sedransk ◽  
Bahadur Singh
Keyword(s):  
Sample Size ◽  
Two Phase ◽  
Sample Size Allocation ◽  
Phase Sampling ◽  
Two Phase Sampling

scholarly journals Optimal sampling schemes based on the anticipated variance with lack of fit

2002 ◽  
Vol 32 (12) ◽  
pp. 2236-2243 ◽  
Author(s):  
D Mandallaz
Keyword(s):  
Estimation Procedure ◽  
Cluster Sampling ◽  
Second Phase ◽  
Optimal Sampling ◽  
Two Phase ◽  
Sampling Schemes ◽  
Lack Of Fit ◽  
Important Improvement ◽  
Phase Sampling ◽  
Simple Stochastic Model

This note presents an important improvement for optimal sampling schemes based on the anticipated variance. The anticipated variance is defined as the average of the design-based variance under a simple stochastic model in which the trees are assumed to be uniformly and independently distributed within a given number of so-called Poisson strata. We consider two-phase two-stage cluster sampling schemes in which costs and terrestrial second-phase sampling density can vary over domains. The estimation procedure is based on post-stratification with respect to so-called working strata that do not need to be identical with the Poisson strata, usually unknown, which induces a lack of fit. It is then possible to derive analytically the optimal sampling schemes. Data from the Swiss National Inventory illustrates the method.

Sign in / Sign up

Export Citation Format

Share Document