Limits to Concurrency*

In the global race to bring new products to market, many firms have adopted concurrent engineering as a technique to shrink development lead time. Due to the many concurrent engineering success stories in the business and engineering literature, a common misconception has grown that more concurrency is always better. The major contribution of this paper is a rigorous demonstration that limits to concurrency exist even in the simplified situation in which concurrency is modeled as the number of design modules to be executed in parallel. As complexities such as communication linkages between modules are layered onto our basic model, we show that the expected project completion time is minimized at a finite number of modules, a number that decreases with increasing problem complexity. In general, the more complex the project, the stricter the limits to concurrency. This strongly suggests that project managers should be cognizant of the potentially adverse effects of pushing concurrency too far.     

Computer Simulation Success: On the Use of the End-User Computing Satisfaction Instrument: A Comment

This comment is part of a comprehensive study to develop a contingency model of simulation success. The current study focuses on the psychometric stability of the end-user computing satisfaction (EUCS) instrument by Doll and Torkzadeh (1988) when applied to users of computer simulation. Using a survey of 411 users, the researchers provide evidence that the EUCS instrument is a valid and reliable measure of computer simulation success. Given this evidence, managers and simulation software product developers can confidently apply the instrument in the investigation of competing tools, features, and technologies.     

An Evaluation of Econometric Models of Adaptive Learning

This paper evaluates the effectiveness of four econometric approaches intended to identify the learning rules being used by subjects in experiments with normal form games. This is done by simulating experimental data and then estimating the econometric models on the simulated data to determine if they can correctly identify the rule that was used to generate the data. The results show that all of the models examined possess difficulties in accurately distinguishing between the data generating processes.     

Fiscal externalities of becoming a parent

Theoretical and empirical results suggest that there are externalities to childbearing, but those results usually assume that these externalities accrue uniformly within a homogeneous population. We advance this argument by developing separate estimates of the fiscal externalities associated with parents—those who devote time or material resources to minor children—and nonparents. Our analysis uses data from the US Panel Study of income Dynamics on the age profiles of taxes paid and publicly funded benefits consumed by parents and nonparents, together with a previously developed intertemporal economic-demographic accounting model. The accounting framework takes into account the net fiscal impacts of future generations as well as the present population. Our findings indicate that, with a 3 percent discount rate, parents produce a substantial net fiscal externality, about $217,000 in 2009 dollars. This is equivalent to a lifetime annuity of nearly $8,100 per year beginning at age 18. The results are sensitive to both the discount rate used and the proportion of parents within the cohort.     

Immigrants assimilate as communities, not just as individuals

The literature on the economic assimilation of immigrants generally treats them as atomistic individuals assimilating in a largely anonymous labour market. Here, we argue that immigrants assimilate as communities, not only as individuals. The longer the immigrant community has been established, the better adjusted it becomes, and the more the host society comes to accept that ethnic group. Using data from a 5% sample of the 1980, 1990 and 2000 US censuses, we find that the stronger is the tradition of immigration from a given source region, the better are the economic outcomes for subsequent immigrants from that source.     

Emulating Parental Levels of Taking Conflict Personally: Associations with Behavioral and Mental Health Outcomes in Adult Children

Taking conflict personally (TCP) is a construct that measures individuals’ tendency to perceive conflict as a personal attack and focus less on the content of a conflict. This study examined parent–child transmissions of the six dimensions of TCP, as well as the relationship between adult child TCP and their conflict communication, depressive symptoms, and anxiety. Data were collected from 110 (N = 330) mother–father–child triads. The results showed significant links between father-child reports of persecuted feelings (i.e., belief that others intentionally provoke conflict) and stress reactions (i.e., psychological reaction) during conflict. There were also significant links between mother–child reports of positive and negative relational effect (i.e., belief that conflict benefits/damages relationships). Adult children’s reports of four of the six TCP dimensions were associated with their depressive symptoms and anxiety, and the results showed significant indirect effects from parent TCP to adult child verbal aggression, constructive conflict, depressive symptoms, and anxiety.     

Advancing Risk‐Informed Decision Making in Managing Defense Nuclear Waste in the United States: Opportunities and Challenges for Risk Analysis

An omnibus spending bill in 2014 directed the Department of Energy to analyze how effectively Department of Energy (DOE) identifies, programs, and executes its plans to address public health and safety risks that remain as part of DOE's remaining environmental cleanup liabilities. A committee identified two dozen issues and associated recommendations for the DOE, other federal agencies, and the U.S. Congress to consider, as well as other stakeholders such as states and tribal nations. In regard to risk assessment, the committee described a risk review process that uses available data, expert experience, identifies major data gaps, permits input from key stakeholders, and creates an ordered set of risks based on what is known. Probabilistic risk assessments could be a follow‐up from these risk reviews. In regard to risk management, the states, in particular, have become major drivers of how resources are driven. States use different laws, different priorities, and challenge DOE's policies in different ways. Land use decisions vary, technology choices are different, and other notable variations are apparent. The cost differences associated with these differences are marked. The net result is that resources do not necessarily go to the most prominent human health and safety risks, as seen from the national level.     

Comparing the effectiveness of behavioral interventions in adults with co-occurring tobacco and substance use disorders: a systematic review of literature

ABSTRACT

This systematic literature review compares the e?ectiveness of various behavioral interventions delivered to persons with co-occurring tobacco and substance use disorders. It examines ?ndings of six randomized trials and three secondary analyses from randomized trials. Based on the ?ndings of this literature review, support is given to the following: (1) The consequences of tobacco use and smoking are deadly, costly, and can have an inhibitory e?ect on the progress of people in substance abuse treatment, (2) tobacco cessation options are a preventive intervention that can be easily incorporated into a treatment facility’s standard of practice and should be made available within the context of all substance abuse treatment facilities, and (3) concurrently treating tobacco use disorder and substance use disorder(s) is an e?ort that will help meet the social work profession’s Grand Challenge to ‘Close the Health Gap.’     

How People Really Suspect and Discover Lies

Previous research suggested that real-world lies are detected through hard evidence, such as physical evidence or a direct confession, and not via nonverbal clues. However, we argue that discovering a lie is a process, and nonverbal clues are an important source of information that can induce suspicion, which then triggers the search for hard evidence. We replicated an original study suggesting the irrelevance of nonverbal clues, but experimentally manipulated the wording of the critical question as ‘discovering’ a lie versus ‘suspecting’ a lie. A second study was conducted that further manipulated the phrasing to ask about ‘events’ versus ‘clues’ that led one to detect the lie. Results of both studies showed that those asked about suspecting a lie cited nonverbal behaviors significantly more often than those asked about discovering a lie. Thus, in contrast to previous research, these findings suggest the importance of behavioral clues (e.g. verbal and nonverbal behavior), specifically in the early stage of lie detection.