OBJECTIVES: To evaluate the utility of using a web-based sample size calculator in the preparation of a research proposal.

METHODS: EpiTools, a free web-based calculator for sample size determination, was used in various study designs.

RESULTS: Computations of sample size needed for several simple epidemiologic study designs were calculated using different assumptions. The calculator was straightforward to use and user- friendly. The results were calculated quickly. Comparison of the computed sample size using different assumptions may be done to assist in evaluating research project feasibility. The input data and output of the sample size calculation may be transformed into a report for inclusion in the written research proposal.

CONCLUSION: The EpiTools web-based calculators is a convenient tool for sample size determination in the design of research protocols in relatively simple study designs. It may be used in evaluating the feasibility of the computed sample size needed by the study design.

.sample Size ; Research Design ; Epidemiologic Research Design ; Writing ; Computers ; Epidemiologic Studies ; Internet

OBJECTIVE:The study aimed to assess the valuation for cigarettes among UP Manila students aged 18-24 through direct and indirect stated preference methods.
METHODS: Direct (iterative bidding) and indirect (discrete choice experiment) stated preference methods were utilized to determine the smokers' Willingness-to-Pay (WTP) and non-smokers' Willingness-to-Accept (WTA). Median and interquartile range were used in describing both WTP and WTA. Fisher's Exact Test and T-test were performed using STATA v12 to determine the association between the identified factors. 
RESULTS: Of the 212 respondents, 21 (9.91%) were smokers. The smokers' direct and indirect WTP for a cigarette stick were PhP 6.00 and PhP 12.43, respectively. There was a significant difference (p=0.01) between the results of the two methods. Meanwhile, 40.84% of the non-smokers could be induced to smoke with PhP 0.00 as their WTA. No significant association was found between the smokers' stated preference and their smoking status and allowance. The WTP of the smokers was higher than the December 2013 retail prices of cigarettes.
CONCLUSION: The increased cigarette prices brought about by the Sin Tax Law were insufficient in stopping the selected UP Manila students to smoke. In addition, forty percent of non-smokers in the study could be induced to smoke. Thus, further price increase of cigarettes, as well as other tobacco control measures, is recommended to discourage smoking among the youth such as college students, specifically in UP Manila.

Human ; Male ; Female ; Adult ; Adolescent ; Tobacco ; Smoking ; Smoke ; Tobacco Use Disorder ; Choice Behavior ; Students ; Surveys And Questionnaires

Introduction: Prematurity-related respiratory disorders are an important public health concern that should be treated efficiently and effectively. Antenatal corticosteroid (ACS) therapy has been recommended to hasten fetal lung maturation in pregnancies at risk but has not been delivered adequately in low to middle-income countries. This study aimed to estimate the treatment effects associated with the use of a single-dose antenatal corticosteroid on the incidence of respiratory-associated morbidity among prematurely delivered neonates. Methods: This was a retrospective cohort study of neonates delivered at 24 to 33 weeks gestation at a tertiary hospital comparing outcomes in those given single-dose ACS with those given no ACS. Association was estimated using logistic and propensity score (PS) analyses, as well as average treatment effect (ATE) and among those treated (ATET). Results: Most neonates (78.11%) received a single dose before delivery (single-dose ACS group) and only a few (21.89%) did not receive any dose (no ACS dose group). The odds ratio of respiratory morbidity in the single-dose ACS group was 0.44 (0.23-0.84) from an adjusted logistic regression model and 0.33 (0.17-0.80) from the PS matching model. The latter model was used to estimate that the average treatment effect from a single-ACS dose on the entire sample was -0.09 (-0.03 to -0.15), while its effect among the actual recipients was -0.08 (-0.02 to -0.15). Conclusion There is a small benefit attributed to the single-dose ACS, reinforcing the need for dose administration and completion. Future studies are recommended to clarify the estimated association and improve on the methodological constraints encountered.
Morbidity ; Propensity Score

Introduction: Despite the growing popularity of utilizing observational studies for determining associations with public health implications, there is limited literature using them for examining and quantifying the effects of exposures or treatments: The study compared traditional regression with scoring approaches in estimating treatment effects considering the noted limitations in the dataset. Methods: We conducted a secondary analysis of previously collected retrospective cohort data derived from maternal-neonatal dyads delivered prematurely in a tertiary hospital. Propensity scores (PS) were estimated using logistic and boosting regression. These scores were implemented into matching, stratification, and weighting models. The estimated measures of effect from traditional regression and PS-adjusted models were compared using certain metrics (i.e., the width of CI, SE, AIC, BIC). Sensitivity analysis was also performed. Results: We included data from 562 patients (123 untreated and 439 treated). Both the estimated scores demonstrated satisfactory fit and reduction in the standardized differences between the groups. However, the logit-estimated scores had better prediction (AUC: 0.71 vs 0.66) and forecasting properties (Brier: 0.15 vs 0.17) than the boosting-estimated scores. All generated statistical models demonstrated a reduction in the occurrence of respiratory morbidity among preterm neonates exposed to a single-dose antenatal corticosteroid (ACS) (ORs ranged from 0.37 to 0.59). The estimated average treatment effects (ATE) and effect among those treated (ATET) from various models suggested a small benefit attributed to the single-dose ACS (ATEs range from -0.09 to -0.41; ATETs range from -0.07 to -0.17). Conclusion PS estimated using logistic regression performed better than those estimated using machine learning strategies. The matching model using the said scores demonstrated better fit and parsimony over conventional and propensity-adjusted models. Future studies are recommended to improve the application of these analytic techniques in real-world data.
Propensity Score ; Machine Learning ; Logistic Models