In their 1992 paper Warner Burke and George Litwin outlined a fairly well thought out integrated I-P-O model of organisational behaviour that embraced exogenous influencers as well as performance output variables. It was presented as a comprehensive causal model based on their vast experience as organisational consultants in the 1980's and 90's. Now a quarter of a century later, is that model still relevant ? Has the model been extended or made more parsimonious over the period ? Is it as relevant to the goods producing sector as it is to the services sector; particularly the knowledge-intensive business sector ?