Health Psychology : a Textbook

MORALITY RATES

At its most basic, a measure of health status takes the form of a very crude mortality

rate, which is calculated by simply counting the number of deaths in one year compared

with either previous or subsequent years. The question asked is, ‘Has the number of

people who have died this year gone up, gone down or stayed the same?’ An increase in

mortality rate can be seen as a decrease in health status and a decrease as an increase

in health status. This approach, however, requires a denominator, a measure of who

is at risk. The next most basic form of mortality rate therefore includes a denominator

reflecting the size of the population being studied. Such a measure allows for com-

parisons to be made between different populations: more people may die in a given year

in London when compared with Bournemouth, but London is simply bigger. In order to

provide any meaningful measure of health status, mortality rates are corrected for age

(Bournemouth has an older population and therefore we would predict that more people

would die each year) and sex (men generally die younger than women and this needs to

be taken into account). Furthermore, mortality rates can be produced to be either age

specific such as infant mortality rates, or illness specific such as sudden death rates. As

long as the population being studied is accurately specified, corrected and specific,

mortality rates provide an easily available and simple measure: death is a good reliable

outcome.

MORBIDITY RATES

Laboratory and clinical researchers and epidemiologists may accept mortality rates as

the perfect measure of health status. However, the juxtaposition of social scientists to the

medical world has challenged this position to raise the now seemingly obvious question,

‘Is health really only the absence of death?’ In response to this, there has been an

increasing focus upon morbidity. However, in line with the emphasis upon simplicity

inherent within the focus on mortality rates, many morbidity measures still use methods

of counting and recording. For example, the expensive and time-consuming production

of morbidity prevalence rates involve large surveys of ‘caseness’ to simply count how

many people within a given population suffer from a particular problem. Likewise, sick-

ness absence rates simply count days lost due to illness and caseload assessments count

the number of people who visit their general practitioner or hospital within a given time

frame. Such morbidity rates provide details at the level of the population in general.

However, morbidity is also measured for each individual using measures of functioning.

MEASURES OF FUNCTIONING

Measures of functioning ask the question, ‘To what extent can you do the following

tasks?’ and are generally called activity of daily living scales (ADLs). For example, Katz

et al. (1970) designed the index of activities of daily living to assess levels of functioning

in the elderly. This was developed for the therapist and/or carer to complete and asked the

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