Question

give example of health conditions that are easy to measure accurately and hard to measure accurately

Answer 1

Health status can be measured using pathological and clinical measures and is usually observed by clinicians or measured using instruments. Types of disease measurement include: Signs - blood pressure, temperature, X-ray, tumour size. Symptoms - disease specific checklists.A Measures of health status
Health status can be measured using pathological and clinical measures and is usually observed by clinicians or measured using instruments.

Types of disease measurement include:

Signs - blood pressure, temperature, X-ray, tumour size
Symptoms - disease specific checklists
Co-morbidity - Charlson Index, ICED- index of co-existing disease (looks at both disease severity and functional severity), adverse events – pain, bleeding, readmission, complications (e.g. using Clavien-Dindo Classification of Surgical Complications).
It is always best to use an existing measure which has been tried and tested rather than inventing a new one. Use an existing standardised measure with proven reliability, validity and responsiveness. Criteria which should be applied when evaluating measures include:

Psychometric criteria

Acceptability - there should be a range across a measure with no floor or ceiling bias
Reliability - test re-test (testing and retesting would give the same score), inter-rater (2 people assessing someone separately would give the same score- measured by the Kappa statistics), internal consistency (Cronbach’s alpha - when series of questions are used to measure something e.g. the Oxford Hip Score, scores for the answers are often on a scale and added up to give a single total numerical value. Scales must have internal consistency i.e. the items should all measure the same thing. Cronbach’s alpha is a coefficient for assessing internal consistency of a scale.Validity – sensitivity (identify those with disease correctly) and specificity (identify those without the disease correctly).Responsiveness - the degree to which a measure can detect change which is clinically meaningful.