This study investigated if part shortages follow the 80-20 rule via a summative content analysis per Hsieh & Shannon. Per the 80-20 rule, 20% of the root-causes result in the 80% of the effects. This represents part of a 423 Billion dollar annual loss in the 10.5 Trillion reviewed markets in 2014 per Gruen, Thomas W., and Daniel Corsten. Part shortages are a root-cause for on-time delivery issues. The study answered the question of do the part shortage root-causes follow the 80-20 rule or not. Per the 80-20 rule, 20% of the root-causes result in the 80% of the effects and issues. This study uses illustrative examples for ease of understanding.