Recent Submissions

  • Relationships between sales of legal medical cannabis and alcohol in Canada

    Armstrong, Michael J. (Elsevier BV, 2022-11)
    The extent to which legalizing cannabis use might lead to increased or decreased alcohol use has important implications for public health, economic growth, and government policy. This study analyzed Canada’s monthly per capita sales of alcohol and legal medical cannabis using fixed effect panel data linear regressions. The data covered seven Canadian regions from January 2011 to September 2018, and controlled for changing levels of retail activity, alcohol prices, tertiary education, unemployment, and impaired driving penalties. The analysis estimated that each dollar of legal medical cannabis sold was associated with an average alcohol sales decrease of roughly $0.74 to $0.84. This suggests that medical cannabis was an economic substitute for alcohol in Canada, and that the country’s 2017-2018 alcohol sales were roughly 1.8% lower than they would have been without legal medical cannabis. The results therefore indirectly imply that reduced alcohol consumption might have partly offset cannabis legalization’s health and economic impacts.
  • Post-CEO retirement appointments and financial accounting—Evidence from CEO turnovers

    Ho, Nam; Pacharn, Parunchana; Brown, Kareen (Wiley Online Library, 2021-11-16)
    Prior research has shown that when boards seek to appoint CEOs as outside directors, the director labor market rewards CEOs’ accounting performance. This study examines whether the external labor market’s assessment of the accounting performance is moderated by CEOs’ past exercise of financial reporting discretion in the form of accruals and real earnings management and financial statement readability. Our results show a positive association between post-CEO board opportunities and within-GAAP accruals management as well as to more readable financial statements. Earnings restatements are associated with fewer board positions and director pay. However, the director labor market appears to punish R&D expenditure above the industry median, suggesting that boards view overinvestment as a risky avenue for growth. Finally, the results suggest that for CEOs with planned retirement, the director labor market provides some mitigating effect on the horizon problem.
  • Interrupted time series analysis of Canadian legal cannabis sales during the COVID‐19 pandemic

    Armstrong, Michael J.; Cantor, Nathan; Smith, Brendan T.; Jesseman, Rebecca; Hobin, Erin; Myran, Daniel T. (Wiley, 2022-03-22)
    Introduction: There were repeated reports of increased cannabis sales, use, and health impacts in Canada during the COVID-19 pandemic. However, it was unclear whether the increases were due to pandemic effects or industry expansion. Methods: We performed interrupted time series regressions of monthly per capita legal cannabis sales from March 2019 to February 2021, first with national averages, then with provincial/territorial data after adjusting for store density. We considered two interruption alternatives: January 2020, when product variety increased; and March 2020, when pandemic restrictions began. Results: The provincial/territorial regression with the January interruption explained R2 = 69.6% of within-jurisdiction variation: baseline monthly per capita sales growth averaged $0.21 (95% CI: 0.15, 0.26), sales immediately dropped in January by $1.02 (95% CI: -1.67, -0.37), and monthly growth thereafter increased by $0.16 (95% CI: 0.06, 0.25). With the March interruption, the regression instead explained 68.7% of variation: baseline sales growth averaged $0.14 (95% CI: 0.06, 0.22), there was no immediate drop, and growth thereafter increased by $0.22 per month, (95% CI: 0.08, 0.35). Discussion: Increasing cannabis sales during the pandemic was consistent with pre-existing trends and increasing store numbers. The extra increased growth was more aligned with January’s new product arrivals than with March’s pandemic measures, though the latter cannot be ruled out. Conclusions: We found little evidence of pandemic impacts on Canada’s aggregate legal cannabis sales. We therefore caution against attributing increased population-level cannabis use or health impacts primarily to the pandemic.
  • Relationships between increases in Canadian cannabis stores, sales, and prevalence

    Armstrong, Michael J. (Drug and Alcohol Dependence, 2021-09-22)
    Background: This study estimated the relationships between increases in legal cannabis stores, legal cannabis sales, and cannabis prevalence in Canadian provinces between 2018 and 2020. Method: Government data were used to calculate changes in licensed store numbers, retail sales dollars, and past-three-month users in 10 provinces across six time periods. The resulting N = 60 observations were standardized per million residents aged 15 and up, and then analyzed via linear regression. Results: Store growth explained 46.3% of the variation in provincial sales growth; each added store was associated with added quarterly sales of $305 (95% CI: $208 to $402) thousand. By contrast, store growth explained only 7.7% of the variation in provincial user growth; each added store was associated with 696 (95% CI: 58 to 1334) added users. Conclusion: From 2018 to 2020, Canada’s rapid cannabis retail expansion was strongly related to legal sales growth but only weakly related to prevalence growth. This implies prevalence growth during that period was related more to legalization’s other aspects and/or to the continuation of already-existing trends.
  • Canada’s provinces and territories should disclose cannabis data to support research

    Armstrong, Michael (Joule Inc, 2021-03-08)
    Despite cannabis legalization’s many potential impacts on Canadian society, provincial governments have disclosed few details about their recreational sales. Detailed proactive data disclosure, like that done in Colorado and Washington state, helps researchers understand legalization’s impacts and suggest regulatory improvements. To ensure Canada’s upcoming regulatory review is evidence-based, provinces must at least start monthly publication of the recreational cannabis sales data they already collect.
  • Legal cannabis market shares during Canada’s first year of recreational legalisation

    Armstrong, Michael (Elsevier, 2020-11-19)
    Background: This study estimated legal products’ share of Canada’s total cannabis consumption during the first year of recreational legalisation, October 2018 to September 2019. Methods: Government data was used to estimate monthly recreational sales in dollars per capita, grams per user, and percentage share of kilograms or litres consumed. As explanatory factors, the analysis considered provincial differences in retail pricing (percentage mark-ups) and store density (stores per million users), as well as national monthly production of dry cannabis (kilograms) and cannabis oil (litres) finished products. Results: Legal recreational products’ share of Canada’s overall cannabis consumption began at 7.8% in October 2018 and grew to 23.7% by September 2019, with an average of 14.5% over the first 12 months. Sales growth was delayed by shortages of both dry cannabis products and licensed stores, but not cannabis oils. Across the 10 provinces, legal recreational shares in September 2019 varied from 13% to 70%; differences in store densities and retail prices partly explained the variation. Prince Edward Island’s large 70% share seemed due to it having minimal product shortages, high store densities, and low prices. Conclusions: Legal recreational products captured market share to the extent they were available, accessible, and low-priced. Problems with those factors slowed the initial expansion of legal product sales but also suggested ways to gradually increase their market share.
  • How gaps between target and midcourse grades impact undergraduates’ studying intentions and grade improvements

    MacKenzie, H.F. "Herb"; Armstrong, Michael (John Wiley & Sons, Inc, 2020-10-09)
    We examine how gaps between students’ chosen target grades and actual midcourse grades relate to their exam studying intentions and subsequent grade improvements. We further investigate whether those relationships are moderated by students’ academic ability (as measured by high school averages) and implicit theory of intelligence or mindset (as measured by questionnaire scores). Our study involved 250 undergraduate students in a first-year business course. The study used linear regression to analyze survey responses at the course’s beginning, survey responses near the course’s end, and actual course grades. The analysis showed students had greater studying intentions and grade improvements when midcourse grades were farther below initial target grades. Mindset moderated the relationship between grade gaps and studying intentions, whereas academic ability moderated the relationship between grade gaps and grade improvements. These results enhance our knowledge of how students respond to grade feedback and could help instructors assist students to make better decisions about their studying.
  • The Effectiveness of Rocket Attacks and Defenses in Israel

    Armstrong, Michael J. (Oxford University Press, 2018-04-11)
    This empirical article studies rocket attacks and defenses in Israel during operations Protective Edge, Pillar of Defense, and Cast Lead, and also during the Second Lebanon War. It analyzes publicly available counts of rockets fired, fatalities, casualties, and property damage. The estimates suggest that interceptor deployment and civil defense improvements both reduced Israel’s losses slightly during Pillar of Defense and substantially during Protective Edge. They also imply that interceptor performance during Pillar of Defense may have been overstated. Ground offensives were the most expensive way to prevent rocket casualties. Interceptors were at least as cost-effective as military offensives, and their advantage improved over time.Without its countermeasures, Israel’s rocket casualties could have been more than fifty times higher during Operation Protective Edge. These results imply that Israel’s rocket concerns were more justified than critics admit, but its military operations were less worthwhile than intended.
  • Students as clients: a professional services model for business education

    Armstrong, Michael (Academy of Management, 2003-12)
    My purpose in this article is to describe a professional services student-as-client model that I believe offers a more realistic guide for core business school operations than either the customer model or the partner model. I begin in the next section by noting the situations where the partner model is well suited, and show why I don't believe it is realistic for most programs. I then define the client analogy, illustrate how it offers a better fit, and describe some of the insights that it suggests.
  • Inventory Flow in Canadian Candy Bar Supply Chains

    Armstrong, Michael J. (APICS, 2011)
    This study examined the ages of candy bars to measure the inventory flow in their supply chains. It sampled 6888 candy bars at 8 retail chains made by 4 manufacturers over a 4 year period. The first objective of the study was exploratory: were there any significant differences in inventory turnover across retailers, manufacturers, or time periods? The second objective was explanatory: could those differences be explained by business events, factory location, market share, or pricing? The analysis showed that there were substantial differences in inventory turnover, especially among the retailers. Unlike in previous research, these differences seemed independent of the particular retail sector. The analysis also found that significant changes in inventory ages coincided with major events at one manufacturer. Interestingly, locating factories close to their markets did not necessarily lead to faster flows. These findings have implications for firms operating in the increasingly integrated North American marketplace.
  • Influence of anticipated and actual grades on studying

    Armstrong, Michael J.; MacKenzie, H.F. (Herb) (Elsevier, 2017-03)
    This study explores two questions regarding differences between students’ anticipated and actual grades in university courses: what factors contribute to those differences arising, and which of those differences influence students’ subsequent studying? The research surveyed 278 students in a first-year undergraduate business course. Students with stronger academic abilities tended to have smaller (less negative) gaps between their grades and goals, while students with higher personal control scores tended to have wider (more negative) gaps. These gaps narrowed later in the course as students’ goals decreased to match their actual grades more closely. Students increased their studying if their actual grades were lower than their original goals, and/or lower than their updated goals. By contrast, the difference between students’ subjective grade goals and their objectively forecast final grades did not influence their studying intentions.
  • A Stochastic Salvo Model Analysis of the Battle of the Coral Sea

    Armstrong, Michael J.; Powell, Michael B. (Military Operations Research Society (MORS), 2005)
    In this work we study the Battle of the Coral Sea using a stochastic version of the salvo combat model. We begin by estimating the range of probable alternative results for the battle, given the forces employed; i.e., if the battle were to be "re-fought", how likely are outcomes other than what historically transpired? Our analysis suggests that a wide range of results was indeed possible, even without any change in forces on either side. We then estimate the impact of hypothetical but plausible changes in the American forces employed. Our analysis suggests that a material advantage could have been obtained by committing extra aircraft carriers to the battle or by dispersing the carriers that were already deployed; on the other hand, equipping each carrier with more fighters but fewer bombers would have yielded a net disadvantage.
  • To repeat or not to repeat a course

    Armstrong, Michael J.; Biktimirov, Ernest N. (Taylor & Francis, 2013)
    The difficult transition from high school to university means that many students need to repeat (retake) one or more of their university courses. This paper examines the performance of students who were repeating first-year core courses in an undergraduate business program. It used data from university records for 116 students who took a total of 232 repeated courses across 6 subjects. The results show that the student’s original course grade and cumulative grade point average were positively associated with the new grade obtained in the repeated course. Conversely, the original course grade was negatively associated with the extent of improvement obtained by repeating.
  • Arbitration using the closest offer principle of arbitrator behaviour

    Armstrong, Michael J.; Hurley, William J. (Elsevier, 2002)
    In this paper we introduce a model of arbitration decision making which generalizes several previous models of both conventional arbitration and final offer arbitration. We derive the equilibrium offers that risk neutral disputants would propose, and show how these offers would vary under different arbitration procedures. In particular, we show that optimal offers made under conventional arbitration will always be more extreme than those made under final offer arbitration.
  • Effects of lethality on naval combat models

    Armstrong, Michael J. (Wiley, 2004)
    In the context of both discrete time salvo models and continuous time Lanchester models we examine the effect on naval combat of lethality: that is, the relative balance between the offensive and defensive attributes of the units involved. We define three distinct levels of lethality and describe the distinguishing features of combat for each level. We discuss the implications of these characteristics for naval decision-makers; in particular, we show that the usefulness of the intuitive concept "more is better" varies greatly depending on the lethality level.
  • A comparison of arbitration procedures for risk averse disputants

    Armstrong, Michael J. (Wiley, 2004)
    We propose an arbitration model framework that generalizes many previous quantitative models of final offer arbitration, conventional arbitration, and some proposed alternatives to them. Our model allows the two disputants to be risk averse and assumes that the issue(s) in dispute can be summarized by a single quantifiable value. We compare the performance of the different arbitration procedures by analyzing the gap between the disputants' equilibrium offers and the width of the contract zone that these offers imply. Our results suggest that final offer arbitration should give results superior to those of conventional arbitration.
  • A stochastic salvo model for naval surface combat

    Armstrong, Michael J. (Institute For Operations Research and Management Science (INFORMS), 2005)
    In this work we propose a stochastic version of the salvo model for modern naval surface combat. We derive expressions for the mean and variance of surviving force strengths and for the probabilities of the possible salvo outcomes in forms simple enough to be implemented in spreadsheet software. Numerical comparisons of the deterministic and stochastic models suggest that while the two models tend to provide similar estimates of the average number of ships surviving a salvo, this average by itself can be highly misleading with respect to the likely outcomes of the battle. Our results also suggest that a navy's preferences for risk (variability) and armament (offensive versus defensive) will depend on not only its mission objectives but also on whether it expects to fight from a position of strength or of weakness.
  • Effective attacks in the salvo combat model: salvo sizes and quantities of targets

    Armstrong, Michael J. (Wiley, 2007)
    This article considers two related questions of tactics in the context of the salvo model for naval missile combat. For a given set of targets, how many missiles should be fired to produce an effective attack? For a given available salvo size, how many enemy targets should be fired at? In the deterministic version of the model I derive a simple optimality relationship between the number of missiles to fire and the number of targets to engage. In the stochastic model I employ the expected loss inflicted and the probability of enemy elimination as the main performance measures, and use these to derive salvo sizes that are in some sense “optimal”. I find that the offensive firepower needed for an effective attack depends not only on a target’s total strength but also on the relative balance between its active defensive power and passive staying power.
  • A survey of the machine interference problem

    Haque, Lani; Armstrong, Michael J. (Elsevier, 2007)
    This paper surveys the research published on the machine interference problem since the 1985 review by Stecke & Aronson. After introducing the basic model, we discuss the literature along several dimensions. We then note how research has evolved since the 1985 review, including a trend towards the modelling of stochastic (rather than deterministic) systems and the corresponding use of more advanced queuing methods for analysis. We conclude with some suggestions for areas holding particular promise for future studies.
  • Refighting Pickett’s Charge: mathematical modeling of the Civil War battlefield

    Armstrong, Michael J.; Sodergren, Steven E. (Wiley, 2015)
    Objective. We model Pickett’s Charge at the Battle of Gettysburg to see whether the Confederates could have achieved victory by committing more infantry, executing a better barrage, or facing a weaker defense. Methods. Our mathematical modeling is based on Lanchester equations, calibrated using historical army strengths. We weight the Union artillery and infantry two different ways using two sources of data, and so have four versions of the model. Results. The models estimate that a successful Confederate charge would have required at least 1 to 3 additional brigades. An improved artillery barrage would have reduced these needs by about 1 brigade. A weaker Union defense could have allowed the charge to succeed as executed. Conclusions. The Confederates plausibly had enough troops to take the Union position and alter the battle’s outcome, but likely too few to further exploit such a success.

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