A measure of the amount of disease associated with an exposure within a population. In a situation in which exposure to a given factor is believed to be a cause of a given disease, the population attributable fraction (or population aetiologic fraction) is the proportion of the disease in the total population that can be attributed to exposure to the factor.
Rates that are specific to the ACT are calculated by dividing the number of ACT resident cases by the ACT population at risk. In some cases, this results in an over-estimate. This occurs with service delivery statistics, where the denominator shows the ACT population, but a high percentage of services are given to non-ACT residents. Consequently (for instance), there may be X number of doctors in the ACT who are servicing the ACT resident population, but they are also servicing non-ACT residents who are not included in the denominator.
Age-specific rates are calculated by dividing the number of cases occurring in each specified five-year age group (and sex) by the corresponding population in the same age group (and sex) and are expressed as an annual rate per 100,000 population.
The standardised rates presented on this website are based on the direct method of standardisation. This method adjusts for effects of differences in the age composition of different populations. The direct age-standardised rates are based on the weighted sum of age-specific (five-year age group) rates in the population. The weights used in the calculation of these rates (the ‘standard’ population) are population ratios for five-year age groups derived from the mid-year 2001 Australian population.
Computer Assisted Telephone Interview
Computer Assisted Telephone Interview (CATI) is a telephone surveying technique that relies on an interviewer reading a questionnaire from a computer screen, and inputting the participants answer as they go.
A person with co-morbidities has more than one disease or condition at the same time (e.g. diabetes and coronary heart disease) that may or may not be causally connected to each other.
A confidence interval (CI) is a computed interval with a given probability (calculated at 95% probability in this report) that a true value of a variable, such as a rate, mean or proportion, is contained within the interval. The confidence interval is the likely range of the true value.
A crude rate is an estimate of a proportion of a population that experiences a specific event over a specified period. It is calculated by dividing the number of events recorded for a given period by the number at risk of the event in the population.
A cumulative rate is the proportion of the population at risk that will develop an outcome in a given period of time. It is a directly standardised rate with equal weights in each age group of interest and zero weight otherwise and is calculated from the age-specific rates. In this report, ages 0-74 years are used as an approximation to an average lifetime. Cumulative rates are often expressed as percentages (rates per 100).
Data linkage is a process of linking information from people held in different data collections together to create a study dataset that contains information about a person, group or population that is relevant to specific health conditions, treatments or outcomes.
Disability Adjusted Life Years (DALYs)
A measure of the burden of disease on a defined population. A DALY is equivalent to the loss of one year of ‘healthy’ life. As such, it is an indication of where health gains can be made.
The DALY extends the concept of potential years of life lost due to premature death (PYLL) by including equivalent years of ‘healthy’ life lost by virtue of being in states of poor health or disability. A DALY for a disease or health condition is calculated as the sum of the years of life lost due to premature mortality (YLL) in the population and the equivalent ‘healthy’ years lost due to disability (YLD) for incident cases of the health condition:
DALY = YLL + YLD where;
YLL = number of deaths at a particular age x standard life expectancy at that age
YLD = incidence x duration x severity weight.
Number of live births in an area during a year, divided by the mid-year female population aged 15-44 in the same area in the same year.
Fetal death refers to death prior to the birth of a baby who did not, at any time after delivery, breathe or show any other evidence of life, such as a heartbeat.
Harm minimisation is a philosophy which underlies many health promotion programs, particularly those focusing on alcohol and other drug use or sexual health. These programs aim to reduce the harmful effects of some behaviours.
A health outcome may be a disease, condition, death, event or a change in health status or behaviour.
Illegal substances or substances used for non-medicinal purposes: speed, cocaine, sleeping pills or tranquilisers, marijuana, analgesics, heroin, petrol and other inhalants, hallucinogens, designer drugs, and injecting of any illegal drug.
Incidence is defined as the number of new cases in a population during a specific period.
Infant mortality rate
The infant mortality rates that appear in this report are based on the number of infant deaths registered in a calendar year, divided by the number of registered births to ACT residents in a given calendar year, multiplied by 1,000.
Life expectancy at birth
Life expectancy at birth is an estimate of the average length of time a person can expect to live, assuming that current rates of death for each age group in the population will remain the same for the lifetime of that person.
Life expectancy data provided have been obtained from ABS reports and referenced accordingly.
The birth of a child who, after birth, breathes or shows any other evidence of life, such as a heartbeat. Perinatal death rates include only infants of at least 20 weeks gestation or where birth-weight is unknown or at least 400 grams birthweight.
Median age at diagnosis is the middle value, i.e. 50% of cancer cases are diagnosed at an older age and 50% at a younger age compared to the median age.
The interquartile range represents the age at which 25% of the cases are above and 25% below the median age. This range spans 50% of the data set and, in effect, eliminates the highest and lowest of outliers because the highest and lowest quartiles are removed.
Mortality refers to deaths in a given population occurring in a specified period.
Death within 28 days of birth of any child who, after delivery, breathed or showed any other evidence of life, such as a heartbeat.
Certification in an approved form of a disease listed in Division 6.1 of the ACT Public Health Act 1997.
Odds ratio (OR) is used to compare the association between a specific exposure and health outcome, two or more populations or to identify factors that play a possible role in health outcome onset. When interpreting an OR, an OR of 1.0 indicates no association, an OR greater than 1.0 indicates higher odds of an outcome, and an OR less than 1.0 indicates a lower odds of an outcome.
The p-value is an expression of the probability that the difference between the observed value and the null value has occurred by chance, or more precisely, has occurred simply because of sampling variability. The smaller the p-value, the less likely the probability that sampling variability accounts for the difference. Typically, a p-value less than 0.05 is used as the decision point, meaning that there is less than a 5% probability that the difference between the observed risk ratio, rate ratio or odds ratio and 1.0 is due to sampling variability. If the p-value is less than 0.05, the observed risk ratio, rate ratio or odds ratio is often said to be statistically significant.
Person-time is an estimate of the actual time-at-risk (in years, months or days) that all participants contributed to a study. In its simplest form, person-time is a sum of each study participant's time at-risk before experiencing the outcome of interest or exiting the study.
Potentially avoidable deaths
Deaths occurring before the age 75 years, which could be avoided by clinical or other healthcare interventions.
Potentially preventable hospitalisations
Potentially preventable hospitalisations are those conditions where hospitalisation is thought to be avoidable if timely and adequate non-hospital care had been provided.
Prevalence is the proportion of a population living with a specific health outcome within a specified time.
Point prevalence is the proportion of existing cases (old and new) in a population at a single point in time. This is different from incidence which is the number of new cases in a given period of time, usually a calendar year.
The first ICD-9 or ICD-10 coding variable reported on the hospital separation form. It means the final diagnosis that best accounts for inpatient care.
Primary Health Network (PHN)
A regional network governed by a Board and consisting of general practitioner-led Clinical Councils and Community Advisory Committees which report to the Board on issues to ensure services across the primary, community and specialist sectors in the region work together. Geographical boundaries of Primary Health Networks (PHNs) are formalised by the Australian Government Department of Health. There is one Primary Health Network in the ACT – Capital Health Network. Primary Health Networks replaced Medicare Locals.
Prohibition orders (related to food safety)
Prohibition orders are served on ACT food businesses to address food safety conditions that represent a serious risk to the public. Conditions that can result in a Prohibition Order include unclean and unhygienic food preparation areas, inadequate storage practices and facilities, inadequate premises maintenance, inadequate hand-washing facilities and infestations of pests such as rats, mice, cockroaches and flies. A Prohibition Order represents a legal direction to a food business to, for example, immediately cease trading.
Rate is the frequency of new cases of the health outcome per unit of person-time.
Relative Standard Errors (RSE)
Relative standard errors (RSE) provide an indication of the reliability of an estimate. Estimates with RSEs less than 25% are generally regarded as ‘reliable’. All estimates presented on this website have RSEs less than 25%, unless otherwise stated. Estimates presented with an RSE between 25% and 50% have been marked with an ‘*’ (asterisk) and should be interpreted with caution. For the purposes of this website, estimates for the ACT with RSEs over 50% were not considered reliable and have not been presented.
Risk is the proportion of an at-risk population that develops a specific health outcome within a specified amount of time. Risks are often reported as a scaled value, such as cases per 1,000, 10,000 or 100,000 population.
A separation (from a hospital) is the process by which an episode of care for an admitted patient ceases.
In statistics, a result is significant if it is considered unlikely to have occurred by chance. When referred to on the website, ‘significant’ implies that a statistical test of significance has been applied. A result was deemed statistically significant (i.e. there is an effect that is considered unlikely to be due to chance alone) if the p-value obtained was less than 0.05, or if comparing confidence intervals, there was no overlap between intervals.
Statistical significance has been assessed in this report by comparing confidence intervals (95% CI) or calculating p-values, depending on the type of data available for hypothesis testing.
Note that statistical significance is different to clinical significance.
Three-year leading average
Three-year leading averages are used to smooth ACT age-standardised rates to better discern trends, by removing fluctuations due to relatively small numbers. For example, the three-year leading average for 2012 would be calculated from the average rates for 2012, 2011 and 2010.
Years Lived with Disability (YLD)
A measure of the years of what could have been a healthy life but were instead spent in states of less than full health. Also called the non fatal burden of disease.
Years of Life Lost (YLD)
The person years of life lost (YLL) provide an indication of the impact of ageing on mortality in a population. Generally, the following formula is used: YLL80 = (80 – age at death) x the number of deaths at each age. (All deaths before 80 years are deemed premature). Also called the fatal burden of disease.
The data is presented by the ACT Government for the purpose of disseminating information for the benefit of the public. The ACT Government has taken great care to ensure the information in this report is as correct and accurate as possible. Whilst the information is considered to be true and correct at the date of publication, changes in circumstances after the time of publication may impact on the accuracy of the information. Differences in statistical methods and calculations, data updates and guidelines may result in the information contained in this report varying from previously published information.