Bayesian Statistics

Vague, variable, subjective to boot…

…and, when used as a basis for decision modelling, helpful for decision makers in NICE technology appraisals

Dr Carole Longson

Appraisal Programme Director

Attributes of Technology Appraisal

• Independent advisory committee formulates guidance

• Transparent and inclusive process

• Consultation with diverse groups

• All groups invited to submit evidence

Attributes of Technology Appraisal• ‘Inclusive’ evidence base, not just

clinical trials

• Multiple perspectives are often conflicting

• Decisions are made in the ‘real world’lack of evidence or conflicting

evidenceconflicting views of the same evidenceuncertainty

Evidence

Research Evidence

Patient Experience

Clinical Practice

What matters?

Need

Size of effect

Value of effect

Service impact

The Appraisal Challenge•Balance the

evidence from different inputs

•Make robust decisions with less than perfect information

•Ensure process is transparent and decisions are justifiable

Independent technology assessment

Patients and carers views and preferences

Health professionals opinion

Modelling the Modelling the unknownunknown

Manufacturers data

Balancing the Evidence

Why we need decision analytic models

• Uncertainty is the norm in technology appraisal!

• Good models help decision makers deal with complex and sometimes conflicting evidence

Why we need decision analytic models?

• To model or not to model?Yes, no choice for many appraisals

• Decision analytic models help make better decisions at time t in the absence of perfect information This is just what the appraisal

process needs

Modelling Techniques and Decision Making

‘The good, the bad, the useful and the not so useful’

We get them all in technology appraisals

"There is nothing more difficult to plan, more doubtful of success, nor more dangerous to manage, than the creation of a new system.

For the initiator has the enmity of all who would profit by the preservation of the old institutions, and merely lukewarm defenders

in those who should gain by the new ones."MachiavellMachiavellii

The Appraisal ChallengeThe Appraisal ChallengeWhat have we learnt?What have we learnt?