Signals for a increased risk of early school-leaving are visible as early as the first year of secondary school. This is one of the findings in the Ph.D. thesis by Ms. T. Traag, researcher at Statistics Netherlands.
The response to a survey will never be 100%, nor will it be completely non-selective. This causes a bias in statistics based on survey research. In this PhD-thesis written by Fannie Cobben various methods for the treatment of nonresponse in sample surveys are described.
There are still many puzzles to be solved concerning the relation between innovation and firm performance, in particular concerning the distinct roles of information and communication technology (ICT) and Research and Development (R&D) in creating new or improved products or production processes. This thesis provides evidence that both instances of innovation are important drivers of productivity and, thus, economic growth. This book consolidates the results of empirical work covering about 10 years of research aimed at understanding the importance for firm performance of innovation in a broad sense.
The subject of this thesis is difficult groups in survey research. Moeilijk waarneembare groepen in enquêteonderzoek is het onderwerp van deze dissertatie
The Ph.D. thesis by Ton de Waal examines two different areas: detection of erroneous data and protection of sensitive data.By assuming that as few errors as possible have been made while answering and processing the questionnaires, the detection of erroneous data can be formulated as a mathematical optimisation problem. In the thesis a number of methods are developed to solve this optimisation problem efficiently. Sensitive data of individual respondents or small groups of respondents have to be protected, for instance by not publishing these data. In the thesis several mathematical problems with respect to protecting sensitive data are explored. For a number of problems, such as calculating the information loss due to protecting sensitive data and minimising the information that is not published, solutions are presented.