An important priority in the current Swedish Defence Bill is to increase the operational warfighting capability of the Swedish Armed Forces, which has implications for the defence supply chain. A recent study suggested that the Swedish Armed Forces should use segmentation of supplies and differentiation of supply chains to enable an affordable supply chain design (SCD). This raises questions regarding which segmentation model and which supply chain strategies (SCSs) the Swedish Armed Forces should use.

The purpose of this research is to design and develop a purchasing portfolio model (PPM) for defence procurement, which will be of practical use for defence authorities. The author defines a PPM as consisting of a segmentation model, tactical levers, differentiation strategies and guidance for management decisions. The research builds on a Delphi study with twenty experts from Swedish defence authorities. It addresses the operational requirements on readiness and sustainability that must be satisfied, as well as research gaps and open issues in the literature regarding PPM design and application.

The findings include several novelties. The author proposes a dynamic PPM, including an innovative two-stage segmentation model, with a precursor and a two-dimensional model. The latter merges sixteen elements into one square and three other segments. Another originality is that the PPM is both prescriptive and serves as a catalyst for in-depth discussions. The author also develops guidance for management decisions, including twelve tactical levers, and eight SCSs to differentiate treatment of the supply segments.

The research contributes to theory by combining constructs from the purchasing and supply management (PSM) literature and supply chain management (SCM) literature, and applying them in the context of military logistics, including defence procurement. It contributes to practice by developing a PPM that is relevant to practitioners in defence procurement and satisfies the operational requirements of the Swedish Armed Forces. It also contributes to methodology by investigating how researchers can use two panels in Delphi studies to enhance research validity.

Purpose

The dual purpose of this paper is to analyse the implications on research rigour of using two panels in a Delphi study, and to take a first step towards investigating how researchers in logistics and SCM establish rigour in Delphi studies.

Design/methodology/approach

Based on a literature review on research rigour in Delphi studies, this paper analyses how a modified design, with two panels, effected research rigour in a Delphi study that produced unexpected results. The paper also conducts a pilot literature review on Delphi-studies in logistics and SCM research, and investigates how these authors establish research rigour.

Findings

This paper finds that with two panels, researchers may enhance rigour in a Delphi study, but also that such a design may lead to results that would be less likely with a conventional design, especially if combined with concluding workshops. The pilot literature review indicates that Delphi-studies in logistics and SCM research establish rigour through the provision of an audit trail, rather than by explicitly discussing the quality criteria of correspondence and/or trustworthiness.

Research limitations/implications (if applicable)

The research indicates limitations with a conventional Delphi design, with one expert panel, and opportunities with a modified design, with two panels. Further research is required to explore these indicative findings.

Original/value

The paper demonstrates how a modified design of the Delphi technique, in combination with concluding workshops, can produce results and insights that would be more difficult to achieve with only one expert panel.

Purpose

Defence supply chains (SCs) aim at operational outcomes, and armed forces depend on them to provide availability and preparedness in peace and sustainability in war. Previous research has focussed on strategies for SCs aiming at financial outcomes. This raises the question of how suitable commercial supply chain strategies (SCSs) are for supply chain design (SCD) in defence. The purpose of this paper is to explain the constructs of SCSs that satisfy military operational requirements and to propose SCSs that are appropriate in defence.

Design/methodology/approach

This paper reports on a Delphi study with 20 experts from Swedish defence authorities. Through three Delphi rounds, two workshops and a validation round, these experts contributed to the reported findings.

Findings

The findings demonstrate that commercial SC constructs are acceptable and applicable in defence but not sufficient. An additional strategy is required to satisfy requirements on availability, preparedness and sustainability. The paper shows that different requirements in peace and war make it challenging to design suitable defence SCs and proposes eight SCSs that satisfy these requirements.

Research limitations/implications

The results emanate from the Swedish defence context and further research is required for generalisation.

Originality/value

This paper extends theory by investigating SCs aiming at operational outcomes. For managers in companies and defence authorities, it explicates how the unique issues in defence must influence SCD to satisfy operational requirements.

This study explains the constructs of a purchasing portfolio model (PPM) that defence authorities can use in practice in defence procurement and designs a segmentation model. We identify open PPM design and application questions in the literature and conduct a Delphi study with twenty experts from Swedish defence authorities to design a segmentation model that is fit-for-purpose. The paper addresses the open design and application questions discussed in the literature and satisfies the operational requirements of the Swedish Armed Forces (SwAF). The proposed segmentation model builds on three dimensions: the operational requirements of the SwAF, the market's ability to deliver supplies on time, and limitations in the SwAF operational capability if the market does not deliver supplies on time. To reduce complexity, we propose a two-stage model in which we use one dimension as a precursor to a two-dimensional model. In the latter, we merge sixteen elements into one square along with three other segments which users should treat differently. The paper contributes to extant academic knowledge on PPMs by eliciting practitioners' views on open design and application questions. We develop the proposed segmentation model in cooperation with practitioners and believe that it will be of value in defence procurement practice.