This paper presents preliminary results from an ongoing empirical study that seeks to understand the relationship between IT-complementary factors and the individual productivity of information workers. Although there is substantial evidence of positive IT complementarity effects on productivity at macro-, meso-, and micro-levels of the economy, we still lack knowledge on the configuration of these factors at the individual level. To investigate this gap, we have designed a new research model of an information worker's individual productivity when an IT system is used jointly and synchronously with both individual and organizational factors. The model is tested in a longitudinal field study of sales operations of an international pharmaceutical company with a multi sub-case setup. While we continue to collect data, preliminary findings from difference-in-difference analysis are presented here and demonstrate that the introduction of a "full" set of IT complementarities has had a positive and significant effect on the number of sales calls performed.