The most recent review covering US dissertations was conducted by Nakhata et al. In this study, the authors reviewed 609 doctoral dissertations completed between 20.
The number of identified dissertations in this study is significantly larger than the four reviews conducted by Stock and colleagues and clearly reflects a significant increase in colleges/universities graduating doctoral students within logistics- and supply chain-related areas.  also point out that a forthcoming retirement of academic “baby boomers” during the period 2005–2020 may explain the increase in the Ph D production.
In this section, nine prior studies—seven American studies and two Nordic studies—are briefly mentioned so as to identify the trends in topical coverage through the years and to see whether there are any similarities between the topics chosen by Ph D students across the Atlantic.
The first study of compendiums of Ph D research in logistics conducted by Stock back in 1987 .
One way to keep track of the progress of logistics and supply chain management (SCM) discipline is to analyze the doctoral dissertations within the research area.
By reviewing such dissertations, it will be possible to gain some interesting information regarding the development and direction of research within the discipline.
Specifically, such a review will help us to understand the different approaches in relation to research framework, methodologies, theories applied and the empirical interpretations.
Furthermore, the review could not only provide valuable insights into potential research gaps within the discipline, but also pave way for recognizing interesting topics for future research .
These efforts provide Ph D students, other academic staff as well as practitioners with an overview of what has been researched within the logistics and SCM area.
These studies have also facilitated the comparison of Nordic dissertations themes to those in the USA (e.g., compiled by Stock  call a relabeling approach between the terms of logistics and SCM.