Eliciting preferences for public goods in non-monetized communities: Accounting for preference uncertainty

One major challenge when conducting contingent valuation studies in developing countries is the choice of the appropriate payment vehicle. Since regular cash-income does not exist for the majority of the population and market integration is low, households in rural areas have less experience with monetary exchanges. In these cases labour time may be a more appropriate payment vehicle. A common finding of studies using labour time as the payment vehicle is that households are more often willing to contribute working time as compared to money. However, so far empirical evidence is missing if the labour time elicitation format reduces respondent’s uncertainty of contributions. In this study we analyze and compare uncertainty of people’s stated willingness to contribute (WTC) time and money for a local public good in a non-monetized small-scale community in Bougainville, Papua New Guinea. We do so by establishing an open-ended method for eliciting people’s WTC, the Range-WTC-method, which elicits the upper and lower bound of a person’s WTC. We find that uncertainty is reduced when respondents are asked for labour time contribution instead of monetary contributions. Thus, we provide empirical evidence that, indeed, labour time is the preferred to money in the elicitation of stated WTC in non-monetized communities

Essays on Climate Change and Adaptation in Developing Countries

This dissertation addresses the issue of adaptation and risk in developing countries. It provides macroeconomic insights into the relationship of climate change, violence and agriculture as well as microeconomic analyses of adaptation, that is, analyzing behavior and related decision making processes of individuals exposed to the risks of climate change.Diese Dissertation befasst sich mit den Themen Adaption und Risiko in Entwicklungsländern. Die Arbeit beinhaltet eine makroökonomische Analyse zum Verhältnis von Klimawandel, Gewalt und Landwirtschaft sowie mikroökonomische Analysen zum Anpassungsverhalten von Individuen die vom Klimawandel und dessen Risiken besonders stark betroffen sind

Social image concerns promote cooperation more than altruistic punishment

Human cooperation is enigmatic, as organisms are expected, by evolutionary and economic theory, to act principally in their own interests. However, cooperation requires individuals to sacrifice resources for each other’s benefit. We conducted a series of novel experiments in a foraging society where social institutions make the study of social image and punishment particularly salient. Participants played simple cooperation games where they could punish non-cooperators, promote a positive social image or do so in combination with one another. We show that although all these mechanisms raise cooperation above baseline levels, only when social image alone is at stake do average economic gains rise significantly above baseline. Punishment, either alone or combined with social image building, yields lower gains. Individuals’ desire to establish a positive social image thus emerges as a more decisive factor than punishment in promoting human cooperation.We acknowledge financial support from the German Federal Ministry of Education and Research through the project ‘BIOACID (03F0655H)’, the Spanish Ministerio de Ciencia e Innovación (grant ECO 2011-23634), the Spanish Ministerio de Economía y Competitividad (project ECO 2015-68469-R), the Universidad Jaume I (P1.1B2015-48) and the Kiel Institute for the World Economy. We especially thank our local assistants Eliuda Maravut, Horai Magum, Philippe Hus, Nigel Henry, Saeleah Gordon and Siko Gordon. We thank Vincent Richrath and Irene Jimenez Arribas for research assistance, and Heike Hennig-Schmidt for discussion

Decrease in treatment intensity predicts worse outcome in patients with locally advanced head and neck squamous cell carcinoma undergoing radiochemotherapy

PURPOSE: Radiochemotherapy (RCT) is an effective standard therapy for locally advanced head and neck squamous cell carcinoma (LA-HNSCC). Nonetheless, toxicity is common, with patients often requiring dose modifications. METHODS: To investigate associations of RCT toxicities according to CTCAE version 5.0 and subsequent therapy modifications with short- and long-term treatment outcomes, we studied all 193 patients with HNSCC who received RCT (70 Gy + platinum agent) at an academic center between 03/2010 and 04/2018. RESULTS: During RCT, 77 (41%, 95% CI 34-49) patients developed at least one ≥ grade 3 toxicity, including seven grade 4 and 3 fatal grade 5 toxicities. The most frequent any-grade toxicities were xerostomia (n = 187), stomatitis (n = 181), dermatitis (n = 174), and leucopenia (n = 98). Eleven patients (6%) had their radiotherapy schedule modified (mean radiotherapy dose reduction = 12 Gy), and 120 patients (64%) had chemotherapy modifications (permanent discontinuation: n = 67, pause: n = 34, dose reduction: n = 7, change to other chemotherapy: n = 10). Objective response rates to RCT were 55% and 88% in patients with and without radiotherapy modifications (p = 0.003), and 84% and 88% in patients with and without chemotherapy modifications (p = 0.468), respectively. Five-year progression-free survival estimates were 20% and 50% in patients with and without radiotherapy modifications (p = < 0.001), and 53% and 40% in patients with and without chemotherapy modifications (p = 0.88), respectively. CONCLUSIONS: Reductions of radiotherapy dose were associated with impaired long-term outcomes, whereas reductions in chemotherapy intensity were not. This suggests that toxicities during RCT should be primarily managed by modifying chemotherapy rather than radiotherapy

Disease-specific assessment of Vision Impairment in Low Luminance (VILL) in age-related macular degeneration – a MACUSTAR study report

Background/Aims: To further validate the Vision Impairment in Low Luminance (VILL) questionnaire, which captures visual functioning and vision-related quality of life under low luminance, low contrast conditions relevant to age-related macular degeneration (AMD). Methods: The VILL was translated from German into English (UK), Danish, Dutch, French, Italian and Portuguese. Rasch analysis was used to assess psychometric characteristics of 716 participants (65% female, mean age 72±7 years, 82% intermediate AMD) from the baseline visit of the MACUSTAR study. In a sub-set of participants (n=301), test-retest reliability (intra-class correlation coefficient, ICC; coefficient of repeatability, CoR) and construct validity were assessed. Results: Four items were removed from the VILL-37 due to misfit. The resulting VILL-33 has three subscales with no disordered thresholds and no misfitting items. No differential item functioning and no multidimensionality were observed. Person reliability and person separation index were 0.91 and 3.27 for the reading subscale (VILL-R), 0.87 and 2.58 for the mobility subscale (VILL-M) and 0.78 and 1.90 for the emotional subscale (VILL-E). ICC and CoR were 0.92 and 1.9 for VILL-R, 0.93 and 1.8 for VILL-M and 0.82 and 5.0 for VILL-E. Reported visionrelated quality of life decreased with advanced AMD stage (p<0.0001) and was lower in the intermediate AMD group than in the no AMD group (p≤0.0053). Conclusion: The VILL is a psychometrically sound patient-reported outcome instrument and the results further support its reliability and validity across all AMD stages. We recommend the shortened version of the questionnaire with three subscales (VILL-33) for future use. Trial registration number NCT03349801

Fundus-controlled perimetry (microperimetry): Application as outcome measure in clinical trials

YesFundus-controlled perimetry (FCP, also called 'microperimetry') allows for spatially-resolved mapping of visual sensitivity and measurement of fixation stability, both in clinical practice as well as research. The accurate spatial characterization of visual function enabled by FCP can provide insightful information about disease severity and progression not reflected by best-corrected visual acuity in a large range of disorders. This is especially important for monitoring of retinal diseases that initially spare the central retina in earlier disease stages. Improved intra- and inter-session retest-variability through fundus-tracking and precise point-wise follow-up examinations even in patients with unstable fixation represent key advantages of these technique. The design of disease-specific test patterns and protocols reduces the burden of extensive and time-consuming FCP testing, permitting a more meaningful and focused application. Recent developments also allow for photoreceptor-specific testing through implementation of dark-adapted chromatic and photopic testing. A detailed understanding of the variety of available devices and test settings is a key prerequisite for the design and optimization of FCP protocols in future natural history studies and clinical trials. Accordingly, this review describes the theoretical and technical background of FCP, its prior application in clinical and research settings, data that qualify the application of FCP as an outcome measure in clinical trials as well as ongoing and future developments