Table 1 Detailed TISP framework (adapted from [15])

Topic identification

Suitable topics are identified for assessment

This stage has three categories:

• Reactive (awaiting input from someone)

• Proactive (actively searching for topics as part of the HTA system’s mandate or work program)

• A mix of proactive and reactive approaches

Examples of proactive approaches include contacting manufacturers, using literature searches and disinvestment strategies. Horizon scanning and early awareness typically is based on a mixture of approaches [14, 46, 47]. Although horizon scanning has been advocated to support collaborative HTA in Europe [7], several countries with experience in HTA such as Thailand [26], most countries in Latin America [25], and many in Europe [48] use simplified approaches to identifying topics

Topic selection (or filtration)

Identified topics are checked for alignment with the aims of the HTA system

For example, if the HTA system has a narrow scope such as childhood vaccination, then vaccines not suitable for children will be excluded. Selection processes may involve technical advice from clinical experts and industry [7, 27]

Topic Prioritization

A decision is made to initiate, reject, or postpone an assessment

While selection ensures that identified topics are aligned with the aims of the HTA system, prioritization is needed when not all identified and selected topics may be assessed at the same depth or through the same process due to limited available resources. Ideally, the purpose is to ensure that topics of greatest impact (to the health system), are adequately assessed in time. Prioritization may follow an explicit or implicit ranking process

Standard prioritization criteria are commonly based on predefined criteria for example, disease burden, availability of other treatment, cost, clinical impact. Criteria like the Pritec tool [20] are used by some HTA agencies. Other agencies may have implicit ranking processes