@article{KlausHoelzelBochetal.2013,
  author    = {Klaus, Valentin H. and H{\"o}lzel, Norbert and Boch, Steffen and M{\"u}ller, Jorg and Socher, Stephanie A. and Prati, Daniel and Fischer, Markus and Kleinebecker, Till},
  title     = {Direct and indirect associations between plant species richness and productivity in grasslands regional differences preclude simple generalization of productivity-biodiversity relationships},
  series = {Preslia : the journal of the Czech Botanical Society},
  volume    = {85},
  journal   = {Preslia : the journal of the Czech Botanical Society},
  number    = {2},
  publisher = {Czech Botanical Soc.},
  address   = {Praha},
  issn      = {0032-7786},
  pages     = {97 -- 112},
  year      = {2013},
  abstract  = {Plant species richness of permanent grasslands has often been found to be significantly associated with productivity. Concentrations of nutrients in biomass can give further insight into these productivity-plant species richness relationships, e.g. by reflecting land use or soil characteristics. However, the consistency of such relationships across different regions has rarely been taken into account, which might significantly compromise our potential for generalization. We recorded plant species richness and measured above-ground biomass and concentrations of nutrients in biomass in 295 grasslands in three regions in Germany that differ in soil and climatic conditions. Structural equation modelling revealed that nutrient concentrations were mostly indirectly associated with plant species richness via biomass production. However, negative associations between the concentrations of different nutrients and biomass and plant species richness differed considerably among regions. While in two regions, more than 40\% of the variation in plant species richness could be attributed to variation in biomass, K, P. and to some degree also N concentrations, in the third region only 15\% of the variation could be explained in this way. Generally, highest plant species richness was recorded in grasslands where N and P were co-limiting plant growth, in contrast to N or K (co-) limitation. But again, this pattern was not recorded in the third region. While for two regions land-use intensity and especially the application of fertilizers are suggested to be the main drivers causing the observed negative associations with productivity, in the third region the little variance accounted for, low species richness and weak relationships implied that former intensive grassland management, ongoing mineralization of peat and fluctuating water levels in fen grasslands have overruled effects of current land-use intensity and productivity. Finally, we conclude that regional replication is of major importance for studies seeking general insights into productivity-diversity relationships.},
  language  = {en}
}
@article{KohlerKreuterStuart2018,
  author    = {Kohler, Ulrich and Kreuter, Frauke and Stuart, Elizabeth A.},
  title     = {Nonprobability Sampling and Causal Analysis},
  series = {Annual review of statistics and its application},
  volume    = {6},
  journal   = {Annual review of statistics and its application},
  publisher = {Annual Reviews},
  address   = {Palo Alto},
  issn      = {2326-8298},
  doi       = {10.1146/annurev-statistics-030718-104951},
  pages     = {149 -- 172},
  year      = {2018},
  abstract  = {The long-standing approach of using probability samples in social science research has come under pressure through eroding survey response rates, advanced methodology, and easier access to large amounts of data. These factors, along with an increased awareness of the pitfalls of the nonequivalent comparison group design for the estimation of causal effects, have moved the attention of applied researchers away from issues of sampling and toward issues of identification. This article discusses the usability of samples with unknown selection probabilities for various research questions. In doing so, we review assumptions necessary for descriptive and causal inference and discuss research strategies developed to overcome sampling limitations.},
  language  = {en}
}
@article{AsendorpfConnerDeFruytetal.2013,
  author    = {Asendorpf, Jens B. and Conner, Mark and De Fruyt, Filip and De Houwer, Jan and Denissen, Jaap J. A. and Fiedler, Klaus and Fiedler, Susann and Funder, David C. and Kliegl, Reinhold and Nosek, Brian A. and Perugini, Marco and Roberts, Brent W. and Schmitt, Manfred and vanAken, Marcel A. G. and Weber, Hannelore and Wicherts, Jelte M.},
  title     = {Recommendations for increasing replicability in psychology},
  series = {European journal of personality},
  volume    = {27},
  journal   = {European journal of personality},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0890-2070},
  doi       = {10.1002/per.1919},
  pages     = {108 -- 119},
  year      = {2013},
  abstract  = {Replicability of findings is at the heart of any empirical science. The aim of this article is to move the current replicability debate in psychology towards concrete recommendations for improvement. We focus on research practices but also offer guidelines for reviewers, editors, journal management, teachers, granting institutions, and university promotion committees, highlighting some of the emerging and existing practical solutions that can facilitate implementation of these recommendations. The challenges for improving replicability in psychological science are systemic. Improvement can occur only if changes are made at many levels of practice, evaluation, and reward.},
  language  = {en}
}