Estimating the lagged effect of price discounting: a time-series study using transaction data of sugar sweetened beverages.

Background: Price discount is an unregulated obesogenic environmental risk factor for the purchasing of unhealthy food, including Sugar Sweetened Beverages (SSB). Sales of price discounted food items are known to increase during the period of discounting. However, the presence and extent of the lagged effect of discounting, a sustained level of sales after discounting ends, is previously unaccounted for. We investigated the presence of the lagged effect of discounting on the sales of five SSB categories, which are soda, fruits juice, sport and energy drink, sweetened coffee and tea, and sweetened drinkable yogurt. Methods: We fitted a distributed lag model to weekly volume-standardized sales and percent discounting generated by a supermarket in Montreal, Canada between 2008 and 2013. Results: While the sales of SSB increased during the period of discounting, there was no evidence of a prominent lagged effect of discounting in four of the five SSB; the exception was sports and energy drinks, where a posterior mean of 28,459 servings (95% credible interval: 2,661 to 67,253) of excess sales can be attributed to the lagged effect in the target store during the study period. Conclusions: Our results indicate that previous studies may have underestimated the effect of price discounting for some food categories.

A Critique of the Random Intercept Cross-Lagged Panel Model

The random intercept cross-lagged panel model (RI-CLPM) is an extension of the traditional cross-lagged panel model (CLPM) that allows controlling for stable trait factors when estimating cross-lagged effects. It has been argued that the RI-CLPM more appropriately accounts for trait-like, time-invariant stability of many psychological constructs and that it should be preferred over the CLPM when at least three waves of measurement are available. The basic idea of the RI-CLPM is to decompose longitudinal associations between two constructs into stable between-person associations and temporal within-person dynamics. The present article critically examines the RI-CLPM from a causal inference perspective. Using formal analysis and simulated data, we show that the RI-CLPM has limited potential to control for unobserved stable confounder variables when estimating cross-lagged effects. The CLPM with additional lag-2 effects sufficiently controls for delayed effects, as long as all relevant covariates are measured. Furthermore, we clarify that, in general, the RI-CLPM targets a different causal estimand than the CLPM. Whereas the cross-lagged effect in the CLPM targets the effect of increasing the exposure by one unit, the within-person cross-lagged effect in the RI-CLPM provides an estimate of the effect of increasing the exposure by one unit around the person mean. We argue that this within-person causal effect is typically less relevant for testing causal hypotheses with longitudinal data because it only captures temporary fluctuations around the individual person means and ignores the potential effects of causes that explain differences between persons.

Daily Beneficial Effects of Work-to-Family Facilitation on Employees' Recovery and General Health: Is More Work Engagement Always Better?

This study of 104 Chilean employees examines the process of WFF—recovery—general health on a daily basis. Drawing on the work–home resources (W-HR) model, we hypothesized that daily work-to-family facilitation and work engagement predict recovery experiences during off-job time in the evening (i.e., detachment from work and relaxation) and subsequent general health at night. Furthermore, we explored whether daily work engagement moderates the relationships between daily work-to-family facilitation and recovery experiences during off-job time in the evening and general health at night. In addition, we expected employees' detachment from work to have a lagged effect on next-day general health at night. Participants completed a survey and a diary booklet over 5 consecutive working days (N = 520 occasions). Multilevel analyses show that, as expected, daily work-to-family facilitation predicted recovery experiences during off-job time in the evening (i.e., detachment from work and relaxation). However, contrary to our expectations, daily work engagement only predicted general health at night. Moreover, as expected, a moderation effect of daily work engagement shows that on days that employees experience low levels of daily work engagement, daily work-to-family facilitation is strongly related to detachment from work and relaxation during off-job time in the evening and to general health at night. Unexpectedly, on days on which employees experienced high levels of daily work engagement, daily work-to-family facilitation was weakly related to these outcomes. Finally, in accordance with our expectations, detachment from work had a lagged effect on next-day general health at night. These findings offer support for the W-HR model and have theoretical and practical implications for research and organizations.

Lagged Effect of Macroeconomic Variables on Stock Returns: A Case of Firm Size

The evidence of lagged effect regarding firm size between macroeconomic factors and stock returns is found with GARCH model for the UAE firms. More precisely, exchange rate showed a significant effect on stock returns irrespective of size group and lag level. However, a positive effect is observed at lag four and a negative effect is observed on lag five and two for small and large size firms respectively. For majority of the firms in small size, the risk-free rate showed a negative lagged effect on stock returns; however, for the majority of the firms in large size, it showed a positive lagged effect on stock returns. Inflation also showed a significant effect on stock returns on each lag level except for large firms where at lag five it is insignificant. Moreover, as the lags increase from 1- 4 and size from small to large, the negative effect of inflation converts to positive effect on stock returns. The lag effect of real activity showed both positive and negative effects on relatively larger stock returns of small firms than big firms. Money supply showed positive significant effect on stock returns of all firms irrespective of the size group; however, this relationship is even more prominent at lag five. Finally, the oil prices showed a positive effect on stock returns (large size) which further maximizes at lag two; whereas, a negative maximization takes place at lag three. Hence, investors can make informed and effective decisions and UAE policymakers developed effective measures to control and promote macroeconomic growth and stability.

Deaths due to COVID-19, Lockdowns, Vaccinations and Weather Temperatures: The Case of Greece

The aim of this paper is to present Greek daily descriptive statistics on confirmed deaths due to COVID-19, the days of lockdown and their effect on the number of deaths, the outcomes of vaccinations and the influence of weather temperatures. Do lockdowns work in bringing the number of deaths down? The descriptive evidence shows that this is the case even though there is a considerable lagged effect. On the other hand, vaccinations, during the time period of examination, do not seem to have diminished the number of deaths, but the reason might be that it takes time for their full effect to occur. Finally, this paper also examines the hypothesis that during the summer months the daily deaths from COVID-19 are relatively lower than during the winter months. Using average daily weather temperatures, this hypothesis cannot be falsified. Simple calculations of the functional relation between weather temperatures and deaths show that temperatures above 28.5 degrees Celsius (°C) were associated with zero deaths. Keywords: COVID-19, deaths, Greece, lockdown, pandemic, vaccinations, weather temperatures