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No empirical evidence to support the hypothesis that daily climate variation has an effect on species’ elevational range size: Reply to Chan et al.
Author(s) -
Field Richard,
Qian Hong
Publication year - 2018
Publication title -
journal of biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 158
eISSN - 1365-2699
pISSN - 0305-0270
DOI - 10.1111/jbi.13372
Subject(s) - range (aeronautics) , econometrics , contrast (vision) , statistics , degrees of freedom (physics and chemistry) , mathematics , variation (astronomy) , structural equation modeling , regression , computer science , artificial intelligence , physics , quantum mechanics , astrophysics , materials science , composite material
Following our critique, Chan et al. defend the approach used in their original paper. They reveal their “iterative strategy of SEM ” (structural equation modelling), which they claim is “standard” (we show otherwise) and “required for the proper and most effective use of SEM ” for hypothesis testing. However, publishing their detailed procedure exposes fundamental flaws: capitalizing on chance and violating important assumptions and principles of SEM . They used the same data to first explore numerous correlations, then fit 29 candidate models (all failed) using the best correlates, then fix model parameters to gain degrees of freedom, then evaluate the “best” model. In producing the “best” model, they fixed five parameters using estimates from regression on the same dataset. They further argue that their stationary bootstrap cures the problems of bias and pseudoreplication; we disagree. At best, Chan et al. developed a hypothesis; they did not perform a valid test of one.