Abstract
Purpose The purpose of this paper is to research the way in which Lean practices are affecting the performance of manufacturing small and medium enterprises (SMEs), analyzing the effects of Lean practices on companies' operational, financial and market performance. Design/methodology/approach An online questionnaire was distributed among Portuguese organizations that fitted the category of SMEs and belonged to the manufacturing sector. A sample of 329 enterprises was analyzed with partial least squares-structural equation modelling. Four hypotheses on the impact of Lean practices on company performance were tested. Findings The results show that the effects of Lean on performance are positive, which stresses the benefits attainable with the implementation of Lean practices. The aggregated implementation of Lean practices, namely, customer involvement, statistical process, continuous flow and total productive maintenance leads to improvements in company's global performance measured by market, financial and operational performance measures, and also improves each of these performance measures individually. It was also noticed that financial capability is one of the indispensable factors for the successful implementation of Lean practices. Originality/value This is the first study that examines the impact of the effect of Lean on operational, financial and market performance in a discriminated and simultaneous way.

Abstract
Studies linking the use of lean practices to company performance have been increasing as markets are becoming more competitive and companies are eager for reducing waste and therefore implementing the Lean Management (LM) philosophy to improve performance. However, results from these studies have found various and different impacts and some light is needed. Extant literature was reviewed and, to achieve the research objective, a meta-analysis of correlations was carried out. The obtained results suggest a positive relationship between some lean practices and performance measures. Furthermore, the presence of moderators influencing the relationship between lean practices and performance outcomes is highlighted in our results. To our best knowledge, this is the first research that proposes a comparison of results from primary studies on Lean implementation, by analysing the linear relationship between lean practices and enterprise performance. It fills this gap and therefore represents an important contribution.

Abstract
The storage policy has a tremendous impact on the efficiency of order-picking operations, which can account for up to 50% of operating costs. The coronavirus pandemic has reinforced the importance of managers making the right operational decisions, namely regarding the definition of the storage policy. It is therefore important to consider handling constraints. This article is inspired by a Portuguese retail company and it considers two handling constraints: weight and shape. We define the location of products by using a zero-one quadratic assignment model. In this model, in addition to the demand and similarity, we considered the weight and shape of the products. We used both weight and shape parameters to set products with similar shapes together, placing aside products with odd shapes. Our analysis shows that the inclusion of the shape and weight into the problem improved the current operations. We found that our method allowed for a reduction of up to 24% in the picking distance, a percentage higher than the one that only considers weight constraints. The inclusion of the shape parameter into the study enabled the company to increase the flow and efficiency of the order-picking operations. Thus, it can be an asset for other warehouses.

Abstract
This paper is inspired by a manual picking retail company where shape and weight constraints affect the order-picking process. We proposed an alternative clustering similarity index that considers the similarity, the weight and the shape of products. This similarity index was further incorporated in a storage allocation heuristic procedure to set the location of the products. We test the procedure in a retail company that supplies over 191 stores, in Northern Portugal. When comparing the strategy currently used in the company with this procedure, we found out that our approach enabled a reduction of up to 40% on the picking distance; a percentage of improvement that is 32% higher than the one achieved by applying the Jaccard index, a similarity index commonly used in the literature. This allows warehouses to save time and work faster.

Abstract
This research establishes a comprehensive chronological and geographical overview of the recent topics mostly debated about the use of Lean thinking in services, disclosing its main trends, gaps and weaknesses. An ample compilation of research from Web of Science and Scopus was examined, and bibliometric analyses were performed, namely publication counting, and abstract, co-citation and co-word analysis. Unfolding Lean implementation projects and evaluating its outcomes are the most frequent themes. Reducing waste and increasing efficiency are often mentioned as the benefits. There are clear gaps in research density between multiple service sectors and healthcare; lack of established models and extensive use of case study method are the weaknesses of the studies in this field. This paper allows Lean practitioners having a sketch of the landscape of this field and its trends. This is the first effort to synthesize those topics in service industry as a whole, using bibliometric methods.

Abstract
A zero-one quadratic assignment model has been proposed for dealing with the storage location assignment problem when there are weight constraints. Our analysis shows that operations can be improved using our model. When comparing the strategy currently used in a real-life company with the designed model, we found that the new placement of products allowed a reduction of up to 22% on the picking distance. This saving is higher than that achieved with the creation of density zones, a procedure commonly used to deal with weight constraints, according to the literature.