The Validity of Conjoint Analysis: An Investigation of Commercial Studies Over Time

Due to more and more online questionnaires and possible distraction—e.g. by mails, social network messages, or news reading during the processing in an uncontrolled environment—one can assume that the (internal and external) validity of conjoint analyses lowers. We test this assumption by comparing the (internal and external) validity of commercial conjoint analyses over the last years. Research base are (disguised) recent commercial conjoint analyses of a leading international marketing research company in this field with about 1.000 conjoint analyses per year. The validity information is analyzed w.r.t. research objective, product type, period, incentives, and other categories, also w.r.t. other outcomes like interview length and response rates. The results show some interesting changes in the validity of these conjoint analyses. Additionally, new procedures to deal with this setting will be shown

Violent behavior among middle school children: The role of gender and personality traits

This paper examines the role of personality traits and gender in violent interaction among middle school children (11-15 age range). The aim of the research presented here was to determine the contribution of personality traits and gender to various aspects of violent interaction, i.e. predisposition towards and exposure to peer violence. The sample consisted of 344 students from 5th to 8th grade, the majority of whom were girls (60.8%). The instruments used in the research were a questionnaire designed to assess violent behavior in primary school children (PRONA) and the Big Five Plus Two inventory (the BF + 2 for children), designed to assess seven basic personality traits in primary school children. The results of a multivariate analysis of covariance suggest that boys tend to perpetrate and be exposed to violent behaviour more than girls, and also that certain personality traits contribute to the manifestation of these constructs. Exposure to violence is determined by low Extraversion, as well as higher levels of Neuroticism and Negative Valence. The traits that contribute most significantly to the tendency towards abusive behaviour are high levels of Aggression and Negative Valence as well as lower levels of Positive Valence. The most effective means of abuse prevention among middle school children is the setting up of prevention programs along with the detection of specific vulnerable groups of students, and the adjustment of these programs to students' personological traits

Video-Based 3D Reconstruction, Laparoscope Localization and Deformation Recovery for Abdominal Minimally Invasive Surgery: A Survey

Background The intra-operative three-dimensional (3D) structure of tissue organs and laparoscope motion are the basis for many tasks in computer-assisted surgery (CAS), such as safe surgical navigation and registration of pre-operative and intra-operative data for soft tissues. Methods This article provides a literature review on laparoscopic video-based intra-operative techniques of 3D surface reconstruction, laparoscope localization and tissue deformation recovery for abdominal minimally invasive surgery (MIS). Results This article introduces a classification scheme based on the motions of a laparoscope and the motions of tissues. In each category, comprehensive discussion is provided on the evolution of both classic and state-of-the-art methods. Conclusions Video-based approaches have many advantages, such as providing intra-operative information without introducing extra hardware to the current surgical platform. However, an extensive discussion on this important topic is still lacking. This survey paper is therefore beneficial for researchers in this field