Costing implementation strategies using Cost-IS: a multiple case study

Implementation strategies often require additional resources, yet their costs are frequently underreported and excluded from economic evaluations. Cost-IS, a data collection instrument for estimating the cost of implementation strategies for digital health innovations, was developed to address this gap. This study retrospectively applied Cost-IS across three health service case studies to estimate implementation strategy costs and identify lessons for future prospective application.

An evaluative, descriptive multimethod multiple case study was conducted. All case studies had completed implementation between 2019 and 2023 in Queensland, Australia. Case study A involved 11 residential aged care homes implementing a hospital avoidance program; case study B spanned three acute tertiary hospitals introducing a digital health solution to improve end-of-life care; and case study C occurred within one tertiary hospital across three wards to enhance inpatient care quality at the end-of-life. Implementation costs were retrospectively estimated using Cost-IS and analysed by strategy mapped to ERIC framework clusters, resource category, and resource type. Feedback from project managers and principal investigators was collected via questionnaires, and improvements to Cost-IS were documented.

When combined across the case studies, implementation costs covered four ERIC clusters: provide interactive assistance (57%), develop stakeholder interrelationships (17%), use evaluative and iterative strategies (16%), and adapt and tailor to context (10%). Labour accounted for 91% of combined implementation costs, with site team resources comprising the majority (63%). Improvements to Cost-IS enhanced data capture granularity, categorisation, and flexibility for analysis. Project managers and principal investigators reported that implementation cost outputs were valuable and useful for reporting and evaluation.

Cost-IS was shown to be a pragmatic instrument for estimating implementation strategy costs across diverse contexts. It worked effectively for retrospective costing and may offer greater benefit when applied prospectively to guide data collection. This paper may also serve as a practical guide for researchers applying Cost-IS in future studies.