An exact test for comparing two predictive values in small‐size clinical trials

Positive and negative predictive values describe the performance of a diagnostic test. There are several methods to test the equality of predictive values in paired designs. However, these methods were premised on large sample theory, and they may not be suitable for small‐size clinical trials because of inflation of the type 1 error rate. In this study, we propose an exact test to control the type 1 error rate strictly for conducting a small‐size clinical trial that investigates the equality of predictive values in paired designs. In addition, we execute simulation studies to evaluate the performance of the proposed exact test and existing methods in small‐size clinical trials. The proposed test can calculate the exact P value, and as a result of simulations, the empirical type 1 error rate for the proposed test did not exceed the significance level regardless of the setting, and the empirical power for the proposed test is not much different from the other methods based on large‐sample theory. Therefore, it is considered that the proposed exact test is useful when the type 1 error rate needs to be controlled strictly.     

Perceptions and Use of Gerotechnology: Implications for Aging in Place

ABSTRACT

Understanding perceptions and use of gerotechnology is crucial to optimize design, application, and education strategies that may reduce caregiver burden, extend healthy aging in place, and minimize demands on the health care system. A pilot project was conducted to explore attitudes, opinions, and preferences of older adults concerning the use of technology to support and extend their ability to “aging in place.” Four major themes emerged as important for older adults to age in place: safety and independence, social interaction, use of technology in the past, and the desire for support. Based on the literature in gerotechnology and the pilot study findings, we present a conceptual model that integrates gerotechnology into the life span theory of control (Heckhausen & Schulz, 1995 Heckhausen, J. and Schulz, R. 1995. A life-span theory of control. Psychological Review, 102(2): 284–304. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Schulz & Heckhausen, 1996 Schulz, R. and Heckhausen, J. 1996. A life span model of successful aging. American Psychologist, 51(7): 702–714. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]) and the concept of aging in place.     

The Reform of Mutual Aid Associations in Japan: Civil Service Employee Pension Reform in 2012

Civil service employee pension reform began by removing non‐clerical work from the main body of the Mutual Aid Association (MAA) pension system. Further changes were based on administrative reform and pension jealousy. In particular, the Nakasone cabinet's administrative reform privatized the non‐clerical sector. Before the 1979 reform, the pensionable age was 55 for the MAA and 60 for the Employee Pension Insurance (EPI) scheme. The MAA pension benefit formula adopted the final salary system, which was larger than the average lifetime salary calculation used for EPI benefits. The final salary system was abolished during the 1986 reform. Public employee criticism over “Amakudari” led to further civil service employee remuneration reform in 2005. In 2007, the Social Insurance Agency pension record scandal led to a change of government by 2009. The biggest reform of the MAA pension system was the abolishment of the occupational portion of the pension, a compromise between the government and unions. We project that this compromise will cost 22 trillion yen over 90 years old. After 2055, the newly established MAA pension scheme will be abolished; thus the public pension may finally be sustainable.     

Do Peers Affect Determination of Work Hours? Evidence Based on Unique Employee Data from Global Japanese Firms in Europe

By using a unique dataset on managerial-level employees who were transferred from Japan to European branches of the same global firms, we examine what would happen to work hours when a worker moves from a long-hour-working country to relatively shorter-hour countries. Even after controlling for business cycles, unobserved individual heterogeneity, job characteristics, and work hour regulations, we find a significant decline in Japanese work hours after their transfer to Europe, resulting from working-behavior influences of locally hired staff. We also find that the reduction in hours worked highly depends on the extent of the workers’ interactions with local peers.     

Quantitative Risk Assessment of Vibrio parahaemolyticus in Finfish: A Model of Raw Horse Mackerel Consumption in Japan

The aim of this study was to evaluate the effects of implemented control measures to reduce illness induced by Vibrio parahaemolyticus (V. parahaemolyticus) in horse mackerel (Trachurus japonicus), seafood that is commonly consumed raw in Japan. On the basis of currently available experimental and survey data, we constructed a quantitative risk model of V. parahaemolyticus in horse mackerel from harvest to consumption. In particular, the following factors were evaluated: bacterial growth at all stages, effects of washing the fish body and storage water, and bacterial transfer from the fish surface, gills, and intestine to fillets during preparation. New parameters of the beta‐Poisson dose‐response model were determined from all human feeding trials, some of which have been used for risk assessment by the U.S. Food and Drug Administration (USFDA). The probability of illness caused by V. parahaemolyticus was estimated using both the USFDA dose‐response parameters and our parameters for each selected pathway of scenario alternatives: washing whole fish at landing, storage in contaminated water, high temperature during transportation, and washing fish during preparation. The last scenario (washing fish during preparation) was the most effective for reducing the risk of illness by about a factor of 10 compared to no washing at this stage. Risk of illness increased by 50% by exposure to increased temperature during transportation, according to our assumptions of duration and temperature. The other two scenarios did not significantly affect risk. The choice of dose‐response parameters was not critical for evaluation of control measures.     

Power-divergence-type measure of departure from symmetry for square contingency tables that have nominal categories

For square contingency tables that have nominal categories, Tomizawa considered two kinds of measure to represent the degree of departure from symmetry. This paper proposes a generalization of those measures. The proposed measure is expressed by using the average of the power divergence of Cressie and Read, or the average of the diversity index of Patil and Taillie. Special cases of the proposed measure include Tomizawa's measures. The proposed measure would be useful for comparing the degree of departure from symmetry in several tables.