هزینه یابی مبتنی بر فعالیت زمان محور در بهداشت و درمان: بررسی مطالعاتی اصولی Time-driven activity-based costing in health care: A systematic review of the literature

1. Introduction Value-based health care (VBHC) has been proposed as a strategy to address the challenges facing health care today [1]. Value is defined in terms of the value equation − health outcomes achieved per unit cost expended over the entire care delivery value chain (CDVC) [2]. The CDVC disregards boundaries between departments and organizations, and captures all processes in the care continuum for a medical condition. Fixed bundled payments to reimburse each CDVC hold providers accountable for the full cycle of care. The ability for providers to compare health outcomes and costs is expected to foster improvement through competition on value. There is currently great interest in VBHC, mostly directed at identifying which health outcomes are appropriate to measure for a particular medical condition [3]. Less attention has been paid to developing a standard for cost calculations [4]. The problem addressed in this paper is that valid value-based comparisons are not possible with- out consensus around how to calculate costs formedical conditions, and if solved, health care providers will be able to understand the cost of care delivery for conditions and control cost. This paper reviews the empirical application of the costaccounting tool, Time-driven activity-based costing (TDABC), presented as the solution to the cost-crisis in health care [5]. In modern competitive reimbursement environments, providers and policy makers are looking for cost-accounting solutions capable of informing process improvement and meeting the expectations of cost-control policies [5–7]. However, previous attempts to develop process-oriented cost-accounting methods in health care, such as Activity-based costing (ABC), have proven challenging. One reason is that it is too resource intensive in large or complex organizations [6,8]. ABC was first applied in health care in the early 1990s [9]. It proved more useful than traditional cost-accounting methods [10,11], but demanded large resource investments, which led to partial or incomplete applications [12]. This was exacerbated by the complexity inherent to health care organizations [13–16]. After peaking in the mid-1990s [12], the subsequent demise of ABC [11] exemplifies the need to find balance between validity in costing and the resources expended to achieve that validity [15,17]. TDABC was presented by Kaplan and Anderson [8] as a modified version of ABC that sought to find this balance. TDABC hasdemonstrated some success in the production and service industries [18]. It prioritizes accuracy over precision, i.e. “approximately right rather than precisely wrong” [6]. Accuracy is how close your cost estimate is to actual cost, and precision is the number of decimal places you include in your estimation. TDABC demands fewer resources by requiring only two key parameters: the capacity cost rate (CCR), and the time required to perform activities in service delivery [8] – thus the name “time-driven” ABC. The CCR is the cost of capacity-supplying resources divided by the practical capacity of those resources. TDABC has been described as a microcosting approach well-suited to accommodate the complexity of cost accounting in health care organizations [5,19]. In 2011, Robert Kaplan and Michael Porter presented a seven-step approach to the application of TDABC in health care settings (Table 1) as the solution to the cost crisis, and linked it to the VBHC agenda [5] (hereafter, all references to TDABC will be to this approach). Given the increasing interest in VBHC and the need to understand the cost of care delivery for medical conditions, the current empirical evidence of TDABC applications in health care should be investigated. Therefore, the aim is to explore why TDABC has been applied, how its application reflects the seven-step model, and what recommendations can be drawn for future applications in health care.