TY  - JOUR
A1  - Becker, Michael
A1  - Lüdtke, Oliver
A1  - Trautwein, Ulrich
A1  - Köller, Olaf
A1  - Baumert, Jürgen
T1  - The differential effects of school racking on psychometric intelligence Do academic-track schools make students smarter?
JF  - The journal of educational psychology
N2  - Prior research has shown that quantity of schooling affects the development of intelligence in childhood and adolescence. However, it is still debated whether other aspects of schooling-such as ability tracking or, more generally, school quality-can also influence intelligence. In this study, the authors analyzed intelligence gains in academic- and vocational-track schools in Germany, testing for differential effects of school quality (academic vs. vocational track) on psychometric intelligence. Longitudinal data were obtained from a sample of N = 1,038 Grade 7 and 10 students in 49 schools. A nonverbal reasoning test was used as an indicator of general psychometric intelligence, and relevant psychological and social background variables were included in the analyses. Propensity score matching was used to control for selection bias. Results showed a positive effect of attending the academic track.
KW  - school quality
KW  - intelligence
KW  - cognitive development
KW  - longitudinal studies
KW  - propensity score matching
Y1  - 2012
U6  - https://doi.org/10.1037/a0027608
SN  - 0022-0663
VL  - 104
IS  - 3
SP  - 682
EP  - 699
PB  - American Psychological Association
CY  - Washington
ER  - 
TY  - JOUR
A1  - Caliendo, Marco
A1  - Clement, Michel
A1  - Papies, Dominik
A1  - Scheel-Kopeinig, Sabine
T1  - The cost impact of spam filters measuring the effect of information system technologies in organizations
JF  - Information systems research
N2  - Dealing with spam is very costly, and many organizations have tried to reduce spam-related costs by installing spam filters. Relying on modern econometric methods to reduce the selection bias of installing a spam filter, we use a unique data setting implemented at a German university to measure the costs associated with spam and the costs savings of spam filters. Our methodological framework accounts for effect heterogeneity and can be easily used to estimate the effect of other IS technologies implemented in organizations.
 The majority of costs stem from the time that employees spend identifying and deleting spam, amounting to an average of approximately five minutes per employee per day. Our analysis, which accounts for selection bias, finds that the installation of a spam filter reduces these costs by roughly one third. Failing to account for the selection bias would lead to a result that suggests that installing a spam filter does not reduce working time losses.
 However, cost savings only occur when the spam burden is high, indicating that spam filters do not necessarily reduce costs and are therefore no universal remedy. The analysis further shows that spam filters alone are a countermeasure against spam that exhibits only limited effectiveness because they only reduce costs by one third.
KW  - spam
KW  - spam filter
KW  - selection bias
KW  - propensity score matching
Y1  - 2012
U6  - https://doi.org/10.1287/isre.1110.0396
SN  - 1047-7047
VL  - 23
IS  - 3
SP  - 1068
EP  - 1080
PB  - INFORMS
CY  - Hannover
ER  -