A Modification of a Method for the Detection of Outliers in Multivariate Samples

Hadi, Ali S.

doi:10.1111/j.2517-6161.1994.tb01988.x

Cited by 290 publications

(212 citation statements)

References 3 publications

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“…This indicates that the linking of the individual and firm data is incomplete. Second, we remove some potentially influential outliers that we detected by using the method proposed by Hadi (1992Hadi ( , 1994. The method is useful for finding multiple outliers in multivariate data.…”

Section: Data and Variablesmentioning

confidence: 99%

How does the age structure of worker flows affect firm performance?

Ilmakunnas

Maliranta

2016

J Prod Anal

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We develop a method for decomposing firm performance to impacts coming from the inflows and outflows of workers and apply it to study whether older workers are costly to firms. Our estimation equations are derived from a variant of the decomposition methods frequently used for measuring micro-level sources of industry productivity growth. By using comprehensive linked employer-employee data, we study the productivity and wage effects, and hence the profitability effects, of the hiring and separation of younger and older workers. The evidence shows that the separations of older workers are profitable to firms, especially in the manufacturing ICTindustries. To account for the correlation of the worker flows and productivity shocks we first estimate the shocks from a production function using materials as a proxy variable. In the second step the estimated shock is used as a control variable in our productivity, wage, and profitability equations.

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Section: Data and Variablesmentioning

confidence: 99%

How does the age structure of worker flows affect firm performance?

Ilmakunnas

Maliranta

2016

J Prod Anal

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“…We also excluded institutions without regional accreditation and those that are non-degree-granting (i.e., grant only certificates). Finally, we used the procedure recommended by Hadi (1994) to identify outliers, and eliminated three institutions with improbably high values for instructional expenditures. 5 The final sample contains 915 community colleges.…”

Section: Dataset and Variablesmentioning

confidence: 99%

IS STUDENT-RIGHT-TO-KNOW ALL YOU SHOULD KNOW? An Analysis of Community College Graduation Rates

et al. 2006

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Over the last decade, policymakers, educators, and researchers have increasingly sought to understand community college policies and practices that promote students' success. This effort has been partly driven by an increased emphasis on outcome accountability, but it has also promoted a productive discussion about improving institutional performance. The research reported here has two related goals. One goal is to work towards strengthening the ability to assess and compare institutional performance. We thus have developed a model that can be used to adjust simple graduation rates for institutional characteristics, such as student composition, college resources, size, and location, all of which might influence those rates. Our long-term goal is to understand how to improve student outcomes, so the paper also uses the model to measure the effect of those institutional characteristics on graduation rates. We use data from the Integrated Postsecondary Education Data System (IPEDS) surveys, applying a weighted least-squares procedure for grouped data to estimate an institutional-completion rates model. This analysis confirms several hypotheses about institutional determinants of graduation rates at community colleges. Our results indicate a consistent negative relationship between enrollment size and completion. Additionally, colleges with high shares of minority students, part-time students, and women have lower graduation rates. A final significant finding among institutional characteristics is that greater instructional expenditures are related to a greater likelihood of graduation. The method developed here can be used to better assess the performance of community colleges.

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“…Outliers have been eliminated using Hadi's method(Hadi 1992(Hadi , 1994.19 A two-sided (parametric bootstrap) test of β war = β allp yields a p = 0.00167.…”

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confidence: 99%

Less fighting than expected

Hörisch

Kirchkamp²

2009

Public Choice

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Demonstration turnout is a crucial political resource for social movements. In this article, we investigate how mass media cover demonstration size. We develop a typology of turnout coverage and scrutinize the factors that drive turnout coverage. In addition, we test whether media coverage underestimates, reflects, or exaggerates "guesstimates" by organizers and police forces. Together, these analyses shed light on whether turnout coverage fits a logic of normalization or marginalization. We rely on a unique dataset of 428 demonstrations organized in Brussels (2003-2010). For these demonstrations, we have information on the turnout as reported in national television news, as counted by the police, and as expected by the organizers. We find that media present turnout most often as a fact, rarely as contentious (10 percent). Although few demonstrations pass the media gates, our study yields little to no evidence for a logic of turnout marginalization. Media coverage does not systematically underestimate demonstration size, nor does it blindly follow police counts. Rather, turnout coverage attests of a logic of normalization, following standard news-making practices. The more important the demonstration (size, lead item) and the larger the gap between police and organizer guesstimates, the more attention is paid to turnout in the news. Discussion centers on the generalizability and normative interpretation of the results.

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A Modification of a Method for the Detection of Outliers in Multivariate Samples

Abstract: SUMMARY We modify a method for identifying outliers in multivariate samples proposed by Hadi. A simulation study shows that this modification controls the size of the test, leads to substantially improved power and is more effective in dealing with the masking and swamping problems.

Cited by 290 publications

References 3 publications

How does the age structure of worker flows affect firm performance?

How does the age structure of worker flows affect firm performance?

IS STUDENT-RIGHT-TO-KNOW ALL YOU SHOULD KNOW? An Analysis of Community College Graduation Rates

Less fighting than expected

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