Evaluating Health System Bottlenecks Using the Tanahashi Model

The outcomes of interest will be informed by Tanahashi’s model for health system evaluation [32 (link)]. Tanahashi argued that health care coverage should not measure the percentage number of people reached but rather measure the percentage of the number of people who received quality service. He then proposed a model to identify and address the barriers to improving effective coverage of interventions. The Tanahashi model consists of five domains (Fig. 4):

Availability coverage: availability of human resources and essential commodities

Accessibility coverage: accessibility of distribution points for interventions

Acceptability coverage: proportion of the population willing to use the service

Contact coverage: proportion of the target population who use the service

Effective/quality coverage: proportion of the target population who received quality and/or satisfactory service

Fig. 4

Adapted from the Tanahashi model for health system evaluation

During the ‘diagnose’ phase of DIVA, the IMT will conduct bottleneck analyses across the Tanahashi model domains to identify constraints to effective coverage of the interventions (preventive, diagnostic, and management modalities). The difference between target coverage and observed coverage for each domain indicator will be identified as a measure of the bottleneck.
Using techniques and tools like brainstorming, the ‘5 whys’ technique, affinity, and driver diagrams, we will guide the IMT to identify immediate, proximal, and distal causes of identified bottlenecks. This step is known as a root cause/causal analysis. In the ‘intervene’ phase, the IMT will brainstorm plausible solutions and strategies to address these bottlenecks. Subsequently, proffered strategies will be converted into action plans along with specific quality/coverage targets for the next implementation quarter. During the ‘verify’ phase, the implementation of planned activities will be monitored through existing supportive supervision, monitoring, and evaluation mechanisms year-round. This will help the early detection of deviation or lag while also optimising the implementation fidelity of planned activities. At any point during verification, implementation challenges identified will be addressed to ensure strategies are carried out as planned and are on track towards attaining targets within stipulated time frames. This forms the ‘adjust’ phase [33 (link), 34 (link)] (Fig. 5).Fig. 5

The process framework for bottleneck identification, analysis, and improvement