My Early Interactions with Jan and Some of His Lost Papers

Abstract

It has been over 40 years since I got to know Jan. This period almost entirely overlaps my career as a psychometrician. During these years, I have had many contacts with him. This paper reviews some of my early interactions, focussing on the following topics: (1) An episode surrounding the inception of the ALSOS project, and (2) Jan's unpublished (and some lost) notes and papers that I cherished and quoted in my work, including (2a) the ELEGANT algorithm for squared distance scaling, (2b) the INDISCAL method for nonmetric multidimensional scaling (MDS), and (2c) notes on DEDICOM.

Keywords

• weighted additive model (WAM)
• alternating least squares (ALS)
• optimal scaling (OP)
• ELEGANT
• indicator method for nonmetric MDS (INDISCAL)
• decomposition into directional components (DEDICOM)