CABFAC factor analysis
This module implements the classical Imbrie & Kipp (1971) method of factor analysis and environmental regression (CABFAC and REGRESS, see also Klovan & Imbrie 1971).
The program asks whether the first column contains environmental data. If not, a simple factor analysis with Varimax rotation will be computed on row-normalized data.
If environmental data are included, the factors will be regressed onto the environmental variable using the second-order (parabolic) method of Imbrie & Kipp, with cross terms. PAST then reports the RMA regression of original environmental values against values reconstructed from the transfer function. Different methods for cross-validation (leave-one-out and k-fold) are available. You can also save the transfer function as a text file that can later be used for reconstruction of palaeoenvironment with a separate module in Past. This file contains:
- Number of taxa
- Number of factors
- Factor scores for each taxon
- Number of regression coefficients
- Regression coefficients (second- and first-order terms, and intercept)
Missing values are supported by column average substitution.
References
Imbrie, J. & N.G. Kipp. 1971. A new micropaleontological method for quantitative paleoclimatology: Application to a late Pleistocene Caribbean core. In: The Late Cenozoic Glacial Ages, edited by K.K. Turekian, pp. 71-181, Yale Univ. Press, New Haven, CT.
Klovan, J.E. & J. Imbrie. 1971. An algorithm and FORTRAN-IV program for large scale Q-mode factor analysis and calculation of factor scores. Mathematical Geology 3:61-77.