Lean is one of the most pervasive phenomena in management practice and literature. Four decades in, it still generates vivid interest and discussion. Few other business phenomena show such popularity and persistence. Taking an evolutionary perspective, the authors study the emergence, growth and maturation of lean from a scholarly perspective. They conduct the most extensive review of the lean literature to date by compiling two datasets: a Primary Lean Dataset consists of 6,920 unique lean articles published in the 35 years following the term’s inception, and a Cited Dataset holds 163,836 unique references cited in the articles in the Primary Lean Dataset. Using bibliometric techniques, the authors analyze where and how lean spreads across application areas, distill its dominant knowledge groups and derive the current trends in the literature. This extensive review contributes a data-driven overview of the evolution and state of the lean literature. Theoretically, it contributes an understanding of lean as an evolving business phenomenon, which holds enough genetic code to evolve and travel across application areas. Recognizing lean’s impressive longevity and travel capabilities, the authors ask whether lean will also be able to prevail through the revolutionary paradigm shift promised by new digital technologies and artificial intelligence, or if lean is now on its last leg. They explore and discuss the details of the lean literature’s past, current and future evolution, and use these rich insights to discuss promising research directions.
Inventory theory is considered one of the original topics in operations management/operations research. Two standard assumptions, homogeneity of customers and exogeneity of demand, are present in the majority of inventory-related academic research. Customers in most practical applications may not be homogeneous as they are affected differently by taste, prices, lead time, service quality, return conditions and other factors. As a result, the retailer faces endogenous demand, as the offered product may not be acceptable for some customers. The decision problems considered here are similar to the decisions of the classical inventory theory, with customer choices present in the environment. This paper names these as inventory problems with heterogeneous customers and endogenous demand. This monograph aims to review the contributions of inventory problems with heterogeneous customers and endogenous demand for a single product. The focal point of the overview is to emphasize the role of considering demand endogeneity for decision-making in inventory systems. The contents include an overview of the issues regarding the use of direct utility functions for customers, a review of the relevant literature, a summary of the possible approaches to solving inventory-related problems with heterogeneous customers and a sketch of three standard inventory models reworked to consider heterogeneous customers. These models are the economic order quantity model, the newsvendor model and the (S−1,S) base-stock model.
This paper reviews the evolution of ridehailing markets and synthesizes the growing academic literature that studies their operational, economic and regulatory foundations. Motivated by the rapid displacement of traditional taxis by transportation network companies such as Uber and Lyft, this paper situates modern ridehailing within its historical and regulatory context and highlights how digital platforms have reshaped labor supply, matching, pricing and service design. The review organizes prior work around core operational levers – driver supply management, matching technologies and service differentiation – and examines how these levers jointly determine passenger wait times, prices, driver utilization and platform performance. This paper then turns to market-level outcomes, including competition between platforms, driver multi-homing, congestion and welfare implications for drivers and passengers, emphasizing how congestion and spatial frictions distinguish ridehailing from canonical two-sided markets. Regulatory responses, including wage floors, worker classification and caps on driver entry, are discussed alongside their operational trade-offs. Finally, this paper considers emerging challenges and opportunities, including the persistence of traditional taxis and the integration of autonomous vehicles. By synthesizing insights across operations management, economics and transportation research, this paper provides a structured framework for understanding ridehailing markets and identifies open questions for future research and policy design.
Most value creation in services takes place in service encounters — at the interfaces between customers, employees, and service organizations. However, managers are often unable to effectively optimize them, because their tools either fail to fully comprehend these interfaces, lying therefore on the fringes of the value creation process, or predate digital technologies. This monograph reviews the recent development of three levers for optimizing service encounters, which lie at the core of the service value creation process and are relevant in a digital world. These levers are: leveraging co-production to innovate in service design; delighting customers through experience design; and fostering employee engagement by putting people first. Given today’s abundant datasets and short feedback loops enabling scientific experimentation, we argue that the time is ripe for effectively optimizing service encounters.
