Competition and Price Dispersion in the U.S. Airline Industry

This papers analyzes dispersion in the prices that an airline charges to different customers on the same route. Such variation in airlines fares is substantial: the expected absolute difference in fares between two of an airline's passengers on a route averages thirty-six percent of the airline's average ticket price on the route. The pattern of price dispersion that we find does not seem to be explained solely by cost differences. Dispersion is higher on more competitive routes, possibly reflecting a pattern of discrimination against customers who are less willing to switch to alternative flights or airlines. We argue that the data support an explanation based on theories of price discrimination in monopolistically competitive industries.

Do Airline Bankruptcies Reduce Air Service?

The airline industry's current financial crisis has raised concerns over the ramifications of airline bankruptcies for air service and the economy. Such bankruptcies, however, nearly always occur when demand is weak, and, thus, when even healthy airlines are inclined to reduce flights. Moreover, from a consumer and policy perspective, the real concern is total air service offered, not the number of flights offered by a particular airline. We study all major U.S. airline bankruptcies since 1984 in order to estimate the effect of bankruptcy on air service, controlling for demand fluctuations and recognizing that competing airlines may increase service in response to a reduction in flights by a bankrupt airline. We do not find substantial effects of bankruptcy on flights offered or destinations served at large and small airports, but do find an impact at medium sized airports. We estimate, however, that service changes due to bankruptcy are not large in comparison to typical quarter-to-quarter fluctuations in service that occur at airports in the absence of carrier bankruptcies.

Do Airlines in Chapter 11 Harm Their Rivals? Bankruptcy and Pricing Behavior in U.S. Airline Markets

The behavior of firms in financial distress has attracted considerable academic and policy interest in recent years. The turmoil in the U.S. airline industry has triggered much of the public policy discussion, as some observers have argued that airlines in financial distress, particularly those operating under Chapter 11 bankruptcy protection, reduce prices to the point of harming themselves and their competitors. This study investigates the pricing strategies of bankrupt airlines and their rivals. The data suggest that an airline's prices typically decline somewhat before it files for bankruptcy protection and remain slightly depressed over the subsequent two or three quarters. We find no evidence that competitors of the bankrupt airline lower their prices, however, nor that they lose passengers to their bankrupt rival. These results indicate that bankrupt carriers do not harm the financial health of their competitors.

Diagrammatic Attention Management and the Effect of Conceptual Model Structure on Cardinality Validation

Diagrams are frequently used to document various components of information systems, from the procedures established for user-system interaction, to the structure of the database at the system’s core. Past research has revealed that diagrams are not always used as effectively as their creators intend. This study proposes a theory of diagrammatic attention management to contribute to the exploration of diagram effectiveness. Based upon diagrammatic attention management, this study demonstrates that the type of diagram most commonly used to represent conceptual models is less effective than three other alternatives for validating the models’ cardinalities. Most conceptual models are documented using entity-relationship diagrams that include a full transaction cycle or module on a single page, i.e., an aggregate diagrammatic format. Participants in this study using three alternative representations (disaggregate diagrammatic, aggregate sentential, and disaggregate sentential) outperformed users of the aggregate diagrammatic format for cardinality validation. Results suggest that to facilitate effective use of aggregate diagrams, users need a mechanism by which to direct their attention while using the diagrams. If such an attention direction mechanism is not inherent in a diagram, it may need to be applied as an external tool, or the diagram may need to be disaggregated to facilitate use

Syk-dependent Phosphorylation of CLEC-2: A Novel Mechanism of Hem-Immunoreceptor Tyrosine-Based Activation Motif Signaling

The C-type lectin-like receptor CLEC-2 signals via phosphorylation of a single cytoplasmic YXXL sequence known as a hem-immunoreceptor tyrosine-based activation motif (hemITAM). In this study, we show that phosphorylation of CLEC-2 by the snake toxin rhodocytin is abolished in the absence of the tyrosine kinase Syk but is not altered in the absence of the major platelet Src family kinases, Fyn, Lyn, and Src, or the tyrosine phosphatase CD148, which regulates the basal activity of Src family kinases. Further, phosphorylation of CLEC-2 by rhodocytin is not altered in the presence of the Src family kinase inhibitor PP2, even though PLCγ2 phosphorylation and platelet activation are abolished. A similar dependence of phosphorylation of CLEC-2 on Syk is also seen in response to stimulation by an IgG mAb to CLEC-2, although interestingly CLEC-2 phosphorylation is also reduced in the absence of Lyn. These results provide the first definitive evidence that Syk mediates phosphorylation of the CLEC-2 hemITAM receptor with Src family kinases playing a critical role further downstream through the regulation of Syk and other effector proteins, providing a new paradigm in signaling by YXXL-containing receptors

Methodological approach for measuring the effects of organisational-level interventions on employee withdrawal behaviour

Background: Theoretical frameworks have recommended organisational-level interventions to decrease employee withdrawal behaviours such as sickness absence and employee turnover. However, evaluation of such interventions has produced inconclusive results. The aim of this study was to investigate if mixed-effects models in combination with time series analysis, process evaluation, and reference group comparisons could be used for evaluating the effects of an organisational-level intervention on employee withdrawal behaviour. Methods: Monthly data on employee withdrawal behaviours (sickness absence, employee turnover, employment rate, and unpaid leave) were collected for 58 consecutive months (before and after the intervention) for intervention and reference groups. In total, eight intervention groups with a total of 1600 employees participated in the intervention. Process evaluation data were collected by process facilitators from the intervention team. Overall intervention effects were assessed using mixed-effects models with an AR (1) covariance structure for the repeated measurements and time as fixed effect. Intervention effects for each intervention group were assessed using time series analysis. Finally, results were compared descriptively with data from process evaluation and reference groups to disentangle the organisational-level intervention effects from other simultaneous effects. Results: All measures of employee withdrawal behaviour indicated statistically significant time trends and seasonal variability. Applying these methods to an organisational-level intervention resulted in an overall decrease in employee withdrawal behaviour. Meanwhile, the intervention effects varied greatly between intervention groups, highlighting the need to perform analyses at multiple levels to obtain a full understanding. Results also indicated that possible delayed intervention effects must be considered and that data from process evaluation and reference group comparisons were vital for disentangling the intervention effects from other simultaneous effects. Conclusions: When analysing the effects of an intervention, time trends, seasonal variability, and other changes in the work environment must be considered. The use of mixed-effects models in combination with time series analysis, process evaluation, and reference groups is a promising way to improve the evaluation of organisational-level interventions that can easily be adopted by others