Term of Award

Summer 2024

Degree Name

Doctor of Philosophy in Logistics and Supply Chain Management (Ph.D.)

Document Type and Release Option

Dissertation (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.


Department of Logistics and Supply Chain Management

Committee Chair

Deepak Iyengar

Committee Member 1

Scott Ellis

Committee Member 2

Alan Mackelprang


In this two-essay dissertation, we analyze the effects of two procurement practices, namely supply base concentration and multi-item procurement, on buyer performance using empirical methods applied to transaction level data at the product category level covering retailers and their suppliers in the Washington cannabis industry. In the first essay, we examine the effects of supply base concentration on procurement prices at the product category level. Using a hierarchical multiple regression approach with ordinary least squares regression and two-way (retailer-supplier) error clustering, we find a U-shaped relationship between supply base concentration and procurement prices, indicating that procurement prices first decrease, but then begin to increase as concentration levels increase. This relationship is moderated by the level of mutual dependence between retailer and focal supplier, such that the U-shape becomes flatter with an increase in mutual dependence. These results suggest that increasing mutual dependence with the focal supplier can ameliorate the negative procurement price effects of excessive supply base concentration. In the second essay, we examine the effects of multi-item procurement on the relationship between product variety and retailer performance. Using a moderated mediation model with seemingly unrelated regression and dyad error clustering, we find a positive indirect effect of product variety on retailer performance via increasing the extent of multi-item procurement. This indirect effect becomes more positive as supplier power advantage increases. These results suggest that retailers who pursue enhanced product variety for its performance benefits should adopt a multi-item procurement strategy, particularly if their supplier has a power advantage.

Research Data and Supplementary Material


Available for download on Thursday, May 31, 2029