Patient-level simulation TSD

A technical support document about patient-level simulation produced by the Nice DSU.



TSD 15: Cost-effectiveness modelling using patient-level simulation (PDF, 494KB)

TSD 15 one-page summary (PDF, 124KB)

Moller J, Davis S, Stevenson M, Cairo J. (2017). Validation of a DICE simulation against a discrete event simulation implemented entirely in code. Pharmacoeconomics


All the documents above are also available in a zip file (.zip, 3.3MB).


Economic models can use either a patient- or cohort-level modelling approach to estimate the expected costs and outcomes across a particular population. In a patient-level simulation, the outcomes are modelled for individual patients and then the average is taken across a sufficiently large sample of patients. In a cohort-level model the outcomes are estimated for the cohort as a whole, without considering the outcomes for individual patients within that cohort.

The aims of this technical support document (TSD) on patient-level simulation are to:

  • Increase awareness of patient-level modelling approaches and highlight the key differences between patient-level and cohort-level modelling approaches.
  • Provide guidance on situations in which patient-level modelling approaches may be preferable to cohort-level modelling approaches.
  • Provide a description of how to implement a patient-level simulation using either a patient-level state-transition or discrete event simulation (DES) framework in a variety of software environments (Microsoft Excel®, R, TreeAge Pro®).
  • Provide example models illustrating how to implement a simple cost-effectiveness model using a patient-level approach. The example models cover both DES (R, Visual Basic module within Microsoft Excel®, TreeAge Pro®) and patient-level state-transition (Microsoft Excel® and TreeAge Pro®) frameworks.
  • Provide guidance on good practice when developing and reporting a patient-level simulation to inform a NICE TA.

The focus of this document is on the application of patient-level simulation to systems where patients can be assumed to be independent as systems incorporating patient interaction are not a common feature with Technology Appraisal.

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