Beyond the more the merrier: The variety effect and consumer heterogeneity in system markets

© 2015 Elsevier B.V. Research in indirect network effects has simplistically treated complementary product variety as the total number of complementary products (e.g., game titles in video game markets). This assumption of equi-differentiation ignores differences across genres or product categories. Furthermore, since consumers with differential preferences for variety enter the market at different stages, consumer heterogeneity in preference for variety in complementary products may evolve as the market develops. We propose a model that recognizes these previously ignored, but important, demand characteristics, and empirically investigate the effects of breadth and depth of software variety on consumer hardware adoption in the fifth-generation video game market. We find that early adopters seek variety across a wide spectrum of game genres, and that late adopters are interested only in action-oriented games and have no interest in strategy-oriented games unless they are so-called superstars. Our findings imply that effective variety planning should be built along both dimensions, instead of simply assuming that more is better. Our policy simulations demonstrate that variety planning is as critical as entry timing to the success of platform companies in system competition, and is one of the reasons for PlayStation\u27s winning the battle against Nintendo64. In addition, the boosting effect of a new title on hardware sales perishes quickly, so it is important to have a cascade strategy to guarantee a continuous supply of complementary software

An empirical analysis of shopping behavior across online and offline channels for grocery products: the moderating effects of household and product characteristics

We study the moderating effects of household (e.g., shopping frequency) and product (e.g., sensory nature) characteristics on household brand loyalty, size loyalty and price sensitivity across online and offline channels for grocery products. We analyze the shopping behavior of the same households that shop interchangeably in the online and offline stores of the same grocery chain in 93 categories of food, nonfood, sensory and nonsensory products. We find that households are more brand loyal, more size loyal but less price sensitive in the online channel than in the offline channel. Brand loyalty, size loyalty and price sensitivity are closely related to household and product characteristics. Light online shoppers exhibit the highest brand and size loyalties, but the lowest price sensitivity in the online channel. Heavy online shoppers display the lowest brand and size loyalties, but the highest price sensitivity in the online channel. Moderate online shoppers exhibit the highest price sensitivity in the offline channel. The online-offline differences in brand loyalty and price sensitivity are largest for light online shoppers and smallest for heavy online shoppers. The online-offline differences in brand loyalty, size loyalty and price sensitivity are larger for food products and for sensory products.This project is partially supported by the Singapore Ministry of Education Research Project R-317-000- 073-113 and the Government of Navarre and the Spanish Ministry of Science Research Project SEC2002- 04321-C02-02

Inhibitory role of peroxisome proliferator-activated receptor gamma in hepatocarcinogenesis in mice and in vitro

Although peroxisome proliferator-activated receptor gamma (PPARγ) agonist have been shown to inhibit hepatocellular carcinoma (HCC) development, the role of PPARγ in hepatocarcinogenesis remains unclear. We investigated the therapeutic efficacy of PPAR

Advertising Bans and the Substitutability of Online and Offline Advertising

The authors examine whether the growth of the Internet has reduced the effectiveness of government regulation of advertising. They combine nonexperimental variation in local regulation of offline alcohol advertising with data from field tests that randomized exposure to online advertising for 275 different online advertising campaigns to 61,580 people. The results show that people are 8% less likely to say that they will purchase an alcoholic beverage in states that have alcohol advertising bans compared with states that do not. For consumers exposed to online advertising, this gap narrows to 3%. There are similar effects for four changes in local offline alcohol advertising restrictions when advertising effectiveness is observed both before and after the change. The effect of online advertising is disproportionately high for new products and for products with low awareness in places that have bans. This suggests that online advertising could reduce the effectiveness of attempts to regulate offline advertising channels because online advertising substitutes for (rather than complements) offline advertising.Google (Firm)WPP (Firm

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Global respiratory syncytial virus–related infant community deaths

Background Respiratory syncytial virus (RSV) is a leading cause of pediatric death, with >99% of mortality occurring in low- and lower middle-income countries. At least half of RSV-related deaths are estimated to occur in the community, but clinical characteristics of this group of children remain poorly characterized. Methods The RSV Global Online Mortality Database (RSV GOLD), a global registry of under-5 children who have died with RSV-related illness, describes clinical characteristics of children dying of RSV through global data sharing. RSV GOLD acts as a collaborative platform for global deaths, including community mortality studies described in this supplement. We aimed to compare the age distribution of infant deaths <6 months occurring in the community with in-hospital. Results We studied 829 RSV-related deaths <1 year of age from 38 developing countries, including 166 community deaths from 12 countries. There were 629 deaths that occurred <6 months, of which 156 (25%) occurred in the community. Among infants who died before 6 months of age, median age at death in the community (1.5 months; IQR: 0.8−3.3) was lower than in-hospital (2.4 months; IQR: 1.5−4.0; P < .0001). The proportion of neonatal deaths was higher in the community (29%, 46/156) than in-hospital (12%, 57/473, P < 0.0001). Conclusions We observed that children in the community die at a younger age. We expect that maternal vaccination or immunoprophylaxis against RSV will have a larger impact on RSV-related mortality in the community than in-hospital. This case series of RSV-related community deaths, made possible through global data sharing, allowed us to assess the potential impact of future RSV vaccines

Cumulative advantage of research productivity : how large is it and who has it

NUS Business School Research Paper Series; 2015-0041-3

CUMULATIVE ADVANTAGE OF RESEARCH PRODUCTIVITY: HOW LARGE IS IT AND WHO HAS IT?

Research Paper Series (National University of Singapore. Faculty of Business Administration); 2012-0091-4