Measuring Health Outcomes

Question 1

Proximal determinants include…

Answer 1

Include individual behaviors

Proximal determinants are viewed as having the most direct effect on health status. Examples include individual behavior such as hand-washing, alcohol and cigarette use), beliefs, attitudes, genetics and biology.

Question 2

Measuring health status of individuals or populations can be used to

Answer 2

Measuring the health status of individuals or populations provides valuable information that can be used for several purposes including measuring the magnitude of disease, conducting surveillance of a disease in a population, improving clinical decisions, and evaluating the effectiveness of programs.

Question 3

Health indicators

Answer 3

Indicators are characteristics that can be measured directly or indirectly and can be used to describe health.

Indicators can be qualitative or quantitative and can measure proximal or distal determinants as well as the disease or illness or instead, positive aspects of health such as quality of life.

Question 4

Composite indicators

Answer 4

Are useful for multi-dimensional concepts that can’t be captured by a single indicator

Indicators can also be indices or composite measures which are formed when individual indicators are compiled into a single index. This is useful for multi-dimensional concepts that can’t be captured by a single indicator

Question 5

Interval scales have no…

Answer 5

Have no true zero point

Interval scales are quantitative in nature, and do not have a true zero point where there is nothing left of the attribute. One advantage of interval scales is that statistical calculations can be performed.

Question 6

The main concepts related to quality of measurement are

Answer 6

Validity and reliability

Question 7

If a scale is incorrectly calibrated and systematically subtracts 10 kg from each weight reading but gives consistent readings, this scale would be

Answer 7

Reliable and invalid

A weight scale that systematically subtracts 10 kg from each respondent’s true weight is reliable because it measures the weight consistently but is not valid because each measurement is 10 kg lower than the true weight.

Question 8

Internal validity is

Answer 8

The degree of certainty that changes in variables in an experimental study are caused by the treatment or intervention

Internal validity refers to the degree to which we are certain that changes in variables in a study are caused by the treatment or intervention. It refers to how well the study was run, including the appropriateness and rigor of research design, how indicators were measured, what wasn’t measured as well as factors such as selection bias and attrition.

Question 9

Criterion validity

Answer 9

Criterion validity measures how well one instrument compares against another instrument or a “gold standard” that is known to be close to the truth. To assess criterion validity of a biological or clinical screening test, one would conduct a sensitivity and specificity assessment where the test is compared against a gold standard method of diagnosis.

Question 10

Sensitivity is

Answer 10

The ability of the test to correctly identify true positives

Sensitivity and specificity assements are an approach to measuring validity and not reliability.

Question 11

Specificity is

Answer 11

Specificity is defined as the ability of a test to correctly identify those who DO NOT actually have the disease, otherwise known as the true negatives.

Question 12

A false negative is

Answer 12

Someone who truly has the disease and who tests negative with the test of interest

Question 13

The negative predictive value

& equation

Answer 13

The negative predictive value (NPV) is the proportion of people who tested negative who actually don’t have the disease
= TN/(TN+FN)

Question 14

Will the sensitivity and specificity of a test always be consistent, regardless of context/population?

Answer 14

No, it will vary in different settings and populations

Question 15

Reliability refers to

Answer 15

Reliability refers to the consistency of a measure, or the degree of stability exhibited when a measure is repeated under identical conditions.

Question 16

Test-retest reliability assesses

Answer 16

Variation in measurements taken by a single person or instrument under the same conditions

Question 17

Inter-observer reliability

Answer 17

Is a measure of agreement between two or more observers measuring the same concept

Question 18

An individual or population’s overall level of health is an example of

Answer 18

Health status

Health status is an individual or population’s overall level of health.

Question 19

Public health concerns

Answer 19

The overall health of groups and the distribution of health within the group

Question 20

Which of the following is true regarding mortality?

Mortality rate is not a useful indicator.
Neonatal mortality rate is the number of deaths of liveborn children under 28 days of age per 100,000 live births per year.
The first known mortality data was collected by John Snow in London.
Neonatal mortality rate is the number of deaths of liveborn children under 28 days of age per 1,000 live births per year.
The crude mortality rate takes into account age.

Answer 20

Neonatal mortality rate is the number of deaths of liveborn children under 28 days of age per 1,000 live births per year.

Traditionally mortality has been the most important indicator of the health status of a population. The first known systematic collection of mortality data was developed by John Graunt, and crude mortality rate does not take into account age. Neonatal mortality rate is typically expressed per 1,000 live births

Question 21

What is a key fact to remember about incidence?

Answer 21

Incidence focuses only on new cases of a disease that occur within a certain period of time

Incidence refers to the number of new cases of a disease that occur during a specified period of time in a population at risk for developing the disease. The denominator, therefore, only includes people who have the potential to develop the disease in the future.

Question 22

In a population of 5,000,000 people at a given time 33,000 people have Disease X. The prevalence is

Answer 22

0.66%

The prevalence is calculated by dividing 33,000 by 5,000,000 and multiplying by 100. This yields a prevalence of 0.66%.

Question 23

Disease Y occurred at a rate of 149/1000 per year in a population of women aged 15-49 who did not previously have Disease Y. This is an example of..

A case fatality rate
An incidence rate
A crude disease rate
A point prevalence rate
A prevalence rate

Answer 23

An incidence rate

The information describes the rate of occurance of a disease within a population who is at risk for developing the disease in the future and thus is an incidence rate.

Question 24

In City A, which has a population of 100,000, there are 200 new cases of tuberculosis reported between January 1, 1998 and December 31, 1998. What is the annual incidence of tuberculosis for this population? Assume that the number of existing cases on January 1 1998 was negligible.

Answer 24

2 per 1,000 per year

There are 200 new cases per year in a population of 100,000. This is equivalent to 2 cases per 1,000 per year.

Question 25

Which of the following is a true statement? The risk of maternal death is most often measured by the neonatal mortality rate The severity of a disease is measured via incidence and prevalence Neonatal mortality rate is usually higher than infant mortality rate A disease’s burden relies on knowing only the proportion of people who have that disease in the population

Answer 25

All of the statements are false. Burden of diseases in a population depends on their frequency (incidence or prevalence), severity (mortality and extent of serious morbidity), consequences (health, social, economic) and type of people affected (gender, age). Risk of maternal death is most often assessed by the maternal mortality ratio. Neonatal mortality, which is defined as the probability of dying within the first month of life, is always less than the infant mortality rate, which is defined as the probability of dying within the first year of life.

Question 26

Prevalence includes:

Answer 26

Existing cases present at a single point in time Prevalence is the number of affected individuals in a population at a specific time divided by the number of persons in a population at that time. Prevalence is essentially a snapshot of the proportion of the population who has the disease at a given moment in time.

Question 27

In Town B, the prevalence of disease Z is 4.6%, and the average duration of the disease is 4 years. What is the incidence rate of the disease?

Answer 27

11.5 per 1,000 In a steady state where rates are not changing and in-migration equals out-migration, prevalence and incidence can be related by the following equation: prevalence = incidence x duration of disease. To calculate incidence rate with the given information, 0.046 is divided by 4 and then multiplied by 1,000 to give a rate per 1,000.

Question 28

If the prevalence of disease J has been roughly constant for the last 10 years, and assuming no other changes, what would be the impact on prevalence of a program that reduces incidence of disease J?

Answer 28

It would decrease prevalence of the disease In a steady state where prevalence is stable, a decrease in incidence of a disease would mean that there are fewer new cases of the disease within a population. This would ultimately lead to a reduction in the prevalence over time.

Question 29

Which of these is a distal determinant of health? Individual behaviors Diet Environmental Factors Tobacco use

Answer 29

Environmental factors Distal determinants have a more indirect effect on a person’s health and tend to be background factors in the sociocultural and environmental context that can predispose people to greater or lower health risks. Examples include cultural factors, education level and the physical environment.

Question 30

DALYs?

Answer 30

DALYs (Disability Adjusted Life Year) assess the number of years lost due to ill health, disability or early death. 1 DALY is equivalent to 1 year of healthy life lost.

Question 31

QALYs

Answer 31

QALYs (Quality Adjusted Life Year), on the other hand, focus on the quality and quantity of life lived.

Question 32

population attributable fraction

Answer 32

Population attributable fraction assesses the percent reduction in incidence rate of a disease that would occur if a certain risk factor were to be eliminated. The population attributable fraction of type 2 diabetes due to physical inactivity is the proportion of incident cases that would be reduced if physical inactivity was eliminated from the population

Question 33

Which of the following statements is true regarding questionnaires? Instruments exist but not all have been validated for use in every setting Instruments exist and can be used in any setting Questionnaires must always be created from scratch

Answer 33

A wide variety of questionnaires for health research exist and are available for use. However, not all of these tools have been validated for every context, so it is important to review evidence for the existing tools before making a decision.

Question 34

Which of the following statements is true? Vital signs are measurements that are invasive. Interview guides are used for collecting qualitative data The Patient Health Questionnaire (PHQ) is used for assessing overall quality of life Field notes include questions and responses the enumerator can either check off or fill in

Answer 34

Interview guides are used for collecting qualitative data Field Notes are the least structured tool for observational data collection and do not include any preset questions or responses. The PHQ is a tool for assessing depression. Vital signs are a non-invasive measurement.

Question 35

Anthropometry

Answer 35

Anthropometry is the measurement of the human body. Anthropometric measures include height, weight, mid-upper arm circumference (MUAC), head circumference and waist and hip circumference. In anthropometry, inter-observer variability can be an issue.

Question 36

MUAC stands for

Answer 36

Mid upper arm circumference | which is measured to assess malnutrition.

Question 37

Which of the following statements is true about dried blood spots? Usually 5 to 6 spots are collected per person They involve collecting finger prick blood on a glass slide Most clinical assays that use venous blood can be performed with dried blood spots They require cold chain

Answer 37

Usually 5 to 6 spots are collected per person Dried blood spots do not require cold chain or glass slides. They involve depositing drops of finger prick blood onto a special type of filter paper card and allowing it to air dry. Usually 5 to 6 drops are collected per person, however the number and range of assays available for dried blood spots is limited.

Question 38

Point of care tests

Answer 38

Are tests that give rapid results on the spot and can be performed by staff with minimal training.

Question 39

Health

Answer 39

Health is a complex multi-dimensional concept. It is usually measured in terms of the absence of physical pain, physical disability, or a condition that could lead to death or disability. As well as in terms of the presence of emotional and mental well-being, and adequate social functioning.

Question 40

proximal determinants

Answer 40

viewed as having the most direct effect on health status. Examples include individual behavior such as hand-washing, alcohol and cigarette use, beliefs, attitudes, genetics, and biology.

Question 41

Distal determinants

Answer 41

have a more indirect effect on a person's health and tend to be background factors in the sociocultural and environmental context that can predispose people to greater or lower health risks. Examples include cultural factors, education level, and the physical environment. For example, low income may lead to poor nutrition and housing.

Question 42

Health status

Answer 42

refers to an individual or population's overall level of health, taking into account various factors such as life expectancy, amount of disability, and levels of risk factors for diseases.

Question 43

Health outcomes

Answer 43

Numerous similar definitions of health outcomes exist. All definitions include a change in health status. Some definitions require that the change be the result of an intervention.

Question 44

health indicator

Answer 44

a characteristic of an individual, population, or the environment that can be measured directly or indirectly. And can be used to describe aspects of the health of individuals or populations. Examples of health indicators include mortality rate, HIV prevalence, percent of children under five who are malnourished, percent of pregnant women delivering in a health facility, consumption of fruit, estimate of work capacity

Question 45

Nominal scales

Answer 45

also called qualitative scales, categorize items based on their name or other quality of classification, and thus have no mathematical interpretation. For example, the variable sex generally has two attributes or categories--male and female. We can assign females a value of 1 and males a value of 2, but these numbers only tell us that males and females are different, but nothing else about that difference. Males are not one unit more of sex than females. The numbers simply represent different categories.

Question 46

Ordinal scales

Answer 46

include variables that have categories with a rank order and a direction, but that have unequal intervals between items. Thus, there is some situational relationship between the categories of the variable . For example, consider a variable for education level with three categories--primary school, secondary school, and post-secondary school. Respondent with secondary school level education has completed more schooling than a respondent with primary school level of education. However, the distances between categories or items on this scale do not have any particular meaning.

Question 47

Interval scales

Answer 47

have a meaningful order and equal intervals between values on the scale, but no true zero point where there's nothing left of that attribute. The distances between the items on the scale have importance. A difference of one unit is the same at any point along the scale. An example of an interval scale is the temperature on the Celsius scale. The difference between 22 and 30 degrees Celsius is the same as the difference between 2 and 10 degrees Celsius. However, because the zero value on the Celsius scale doesn't reflect the absence of temperature, we can't calculate ratios or proportions.

Question 48

Ratio scales,

Answer 48

the most precise level of measurement, have all of the qualities of interval scales and in addition, have a true zero point at which nothing is left of the attribute. Ratio scales are the most common type of measurement in the sciences and include examples such as weight, length, and grade point average or GPA.

Question 49

Validity

Answer 49

efers to the degree at which a method, test, or measuring device measures what it intends to measure.

Question 50

Internal validity

Answer 50

refers to the degree to which we are certain that changes in variables in a study are caused by the treatment or intervention. It refers to how well the study was run, including the appropriateness and rigor of research design, how indicators were measured, what wasn't measured, as well as factors, such as selection bias and attrition.

Question 51

External validity

Answer 51

refers to the degree to which study findings are applicable to other populations and contexts. This is also called generalizability.

Question 52

Face validity

Answer 52

an assessment of whether a measure appears to measure the target concept.

Question 53

Content validity

Answer 53

a subjective assessment of the extent to which a measure adequately represents all facets of a concept.

Question 54

Criterion validity

Answer 54

measures how well one instrument compares against another instrument, or a gold standard, that's known to be close to the truth. Criterion validity is generally quantified by assessing correlation coefficients between the survey measure and the criterion or gold standard. The higher the correlation, the greater the validity of the instrument or measure.

Question 55

predictive validity.

Answer 55

Criterion validity can be assessed by comparing both instruments at the same point in time, which is called concurrent validity, or by giving the target test first and measuring whether it predicts the findings of the gold standard tests at a later time.

Question 56

construct validity

Answer 56

refers to how well the scale or instrument measures the construct that it is intending to measure. It requires assessing relationships between a study variable and other variables that are being measured in the study that are known via theory or other evidence to be related. The more often these relationships are confirmed, the greater the construct validity of the survey variables.

Question 57

Sensitivity & equation

Answer 57

defined as the ability of a test to correctly identify those who actually have the disease. These are also known as true positives. calculated as the number of true positives divided by the sum of the true positives and false negatives. TP/ (TP + FN)

Question 58

Specificity & equation

Answer 58

defined as the ability of a test to correctly identify those who do not actually have the disease. These are also known as the true negatives. calculated as the number of true negatives divided by the sum of the true negatives and false positives. TN/(TN + FP)

Question 59

positive predictive value

Answer 59

the proportion of people who tested positive who actually have the disease. Or in other words, it's the probability that someone with a positive test result actually has the disease

Question 60

negative predictive value

Answer 60

the proportion of people who tested negative who actually don't have the disease. Or in other words, the probability that someone who tests negative actually doesn't have the disease.

Question 61

Tradeoff between sensitivity and specificity

Answer 61

It is important that both characteristics are high. However, sometimes it may be more important to have very high sensitivity, such as when a missed diagnosis may lead to death of a patient, even at the expense of high specificity, where false negatives may mean drug may be prescribed and wasted and some other diagnosis may be delayed.

Question 62

Sensitivity and specificity in different populations

Answer 62

Sensitivity and specificity may vary in different settings and populations. And it's important to look for assessments in a population very similar to your population of interest. If no published literature on sensitivity and specificity of the test of interest exist, consider assessing it yourself before deciding to use it.

Question 63

Reliability

Answer 63

refers to the consistency of a measure or the degree of stability exhibited when a measure is repeated under identical conditions. Essentially, this refers to how consistent the answers people give to a question are when they're asked at different points in time, assuming that no real changes have occurred.

Question 64

three approaches to assess reliability

Answer 64

test/re-test reliability inter-observer or inter-rater reliability internal consistency.

Question 65

test/re-test reliability

Answer 65

assessing whether the same question or measure yields consistent results at different points in time It can, for example, be measured by administering the same survey to the same individuals at two different points in time to assess the correlation between the two sets of scores. This is usually quantified with a correlation coefficient. If the correlation between the repeated measures is higher than 0.7, than the test retest reliability is high.

Question 66

inter-observer or inter-rater reliability

Answer 66

assessing whether different people collecting data on the same question get similar answers - inter-observer or inter-rater reliability could occur due to variations in measurement techniques between observers, as well as variations in interpretations of measurements. Inter-observer reliability can be assessed with co-relation coefficients. In general, a correlation between or among enumerators of 0.8 or higher is targeted.

Question 67

internal consistency.

Answer 67

assessing whether different questions that are trying to measure the same concept are correlated. Some ways to improve reliability include having clear and detailed measurement protocols, ensuring thorough training and sufficient practice, conducting regular evaluations, using appropriate measurement tools or equipment, and ensuring that equipment is properly maintained.

Question 68

Intra-individual variability

Answer 68

defined as variations in an individual's physiological or behavioral characteristics over time.

Question 69

Intra-observer variability

Answer 69

random error in measurement made by the same observer on the same subject

Question 70

three approaches to measuring population health.

Answer 70

○ Aggregating health outcome measurements made on individuals into summary statistics, such as population averages or medians. ○ Assessing the distribution of individual health outcome measures in a population and among specific population subgroups. ○And measuring the function and well-being of the population or society itself, as opposed to individual members.

Question 71

The relative importance, or burden, of different diseases in a population depends on several key factors.

Answer 71

○ Their frequency, which refers to incidence or prevalence. ○ Severity, which depends on mortality and the extent of serious morbidity. ○ Consequences, which could be health, social, or economic consequences. ○ And the type of people affected, their gender, and age, and so on.

Question 72

mortality

Answer 72

The number of deaths in a population over a specific period of time, usually a year, divided by the size of the population is the population's crude mortality rate. The mortality rate can serve as a measure of disease severity, as well as an indicator of whether interventions have been successful over time.

Question 73

Common mortality indicators include

Answer 73

include annual mortality rate, infant mortality rate, child mortality rate, neonatal mortality rate, and the maternal mortality ratio. Other indicators include case fatality and proportionate mortality.

Question 74

life expectancy at birth

Answer 74

Life expectancy at birth is the average number of additional years a newborn baby could expect to live if there is no change in the rate of death during the rest of the newborn's life.

Question 75

Infant mortality rate

Answer 75

It refers to the number of deaths of infants less than one year of age per 1,000 live births in a given year. Thus, it measures how many infants younger than one will die for every 1,000 who are born in a given year The lower the rate, the better the health status of the population.

Question 76

Under 5 mortality rate

Answer 76

the number of deaths of children under five years of age per 1,000 live births in a given year, is also a commonly used indicator.

Question 77

Maternal mortality ratio

Answer 77

captures the risk of death associated with pregnancy, labor, and the postpartum period

Question 78

morbidity

Answer 78

refers to sickness or departure from a psychological or physiological state of well-being, whether subjective or objective.

Question 79

Morbidity indicators

Answer 79

Morbidity indicators show the burden that a disease has on a population. It can be measured using rates which tell us how fast the disease is occurring in a population and proportions, which tell us what fraction of the population is affected.

Question 80

Incidence

Answer 80

refers to the number of new cases of a disease that occur during a specified period of time in a population at risk for developing the disease. it captures disease in a population of individuals who don't have the disease at baseline but have the potential to develop the disease within a specified time period. The critical points to remember about incidence include that the focus is only on new cases. And therefore, this indicator is a measure of risk.

Question 81

Incidence rate

Answer 81

Number of new cases of disease in a population in a specified period of time divided by the total person-time x 1000 *the answer will be written as # per 1000 person years

Question 82

total person-time

Answer 82

Sum of time periods of observation of each person who has been observed for all or part of the entire time period

Question 83

How do researchers deal with individuals lost in the follow-up when estimating the total person-time?

Answer 83

Typically, researchers assume that individuals lost to follow up were on average disease-free for half of the specific follow-up period.

Question 84

Prevalence

Answer 84

the number of affected individuals in a population at a specific time divided by the number of persons in a population at that time. Prevalence is essentially a snapshot of the proportion of the population who has the disease at a given moment in time. Prevalence does not tell us when the disease developed, so it comprises people who are newly diagnosed along with people who've had the disease much longer.

Question 85

Prevalence equation

Answer 85

Number of cases divided by the number of people in the population (vs. Incidence rate = number of NEW cases / total person time x 1000)

Question 86

Point prevalence

Answer 86

the proportion of people who had the disease at a specific point in time, such as today

Question 87

period prevalence

Answer 87

refers to the proportion of people who had the disease at any time during a certain period, such as a calendar year. Typically, for the period prevalence calculation, the denominator consists of the average or mid-interval population.

Question 88

Prevalence & incidence relationship (equation)

Answer 88

Prevalence equals incidence times duration of disease.

Question 89

How are the sum of DALY's used?

Answer 89

The sum of DALYs across a population is the overall burden of disease in that population, or put another way, the difference between the population's current health status and an ideal where people live free of disease and disability. DALYs were designed to allow international comparisons. DALYs for a specific disease or health condition are calculated by adding the years of life lost due to premature mortality, or the YLL, and the years of life lost due to disability, or the YLD.

Question 90

years of life lost due to premature mortality, or the YLL

Answer 90

takes into account the age at which the death occurs by giving higher weights to earlier deaths

Question 91

the years of life lost due to disability, or the YLD

Answer 91

YLD is a measure of healthy years lost due to disease or injuries. To calculate the YLD for a specific disease during a specific time period, multiply the number of incident cases of that disease by the average duration of the case until death or cure, and also by a factor that reflects the severity of the disease.

Question 92

QALY equation

Answer 92

we multiply the length of life, usually in years, by the quality of life.

Question 93

Quality of life is measured by...

Answer 93

Quality of life is measured on a scale of 0-1 with 1 being equivalent to perfect health and 0 being equivalent to death. These qualities of life valuations, or health utilities, can be generated using a number of approaches, including patient questionnaires.

Question 94

GINI index

Answer 94

The GINI index measures the extent to which income distribution among a population deviates from the theoretical line of equality in which each segment of the population earns the same proportion of the total income.

Question 95

Concentration index

Answer 95

Adapted version of the GINI index. It indicates the extent to which a health indicator is concentrated among disadvantaged or advantaged groups in a population - to capture the distribution of health inequality across populations

Question 96

Population Attributable Fraction

Answer 96

assesses the percent reduction in incidence rate of a disease that would occur if a certain risk factor were to be eliminated.

Question 97

self-reported measures

Answer 97

respondents provide information on their own knowledge, attitudes, and behaviors.

Question 98

Observational measures

Answer 98

involve careful systematic observation of behaviors, factors related to health, events, or physical characteristics of the environment.

Question 99

Biological and clinical data

Answer 99

involves collection of physical measures such as weight, physiological measures, as well as testing for presence or absence of diseases.

Question 100

Electronic measures

Answer 100

involve utilizing technologies to record occurrence of specific target behaviors or events