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Studying at Cambridge

DAPA Measurement Toolkit

Glossary

;

A

Absolute reliability - The agreement between replicate measures of the same phenomenon using the same method and units.
Absolute validity - The agreement between two methods measuring the same phenomenon with the same units.

B

Basal metabolic rate (BMR) - The rate of energy expenditure of an individual in a fasted state at complete rest the morning after sleep in a temperature neutral environment. This is the rate of energy expenditure required to maintain cellular functions.
Basal energy expenditure - The sum of energy expended by an individual in a fasted state at complete rest the morning after sleep in a temperature neutral environment during a specified time period. This is the energy expenditure required to maintain cellular functions.
Between-individual - The degree to which a characteristic is higher or lower for different people. For example, swimming participation and broccoli consumption likely differ by individual.
Bias - The cumulative effect of deviation of observations from truth.
Bioavailability - The proportion of nutrient in foods that are digested, absorbed and metabolised through normal pathways.

C

Compendium of physical activities - Activity cost table published by Ainsworth et al. (2011). Describes 821 activity types in terms their Metabolic Equivalent Task or MET , which is the multiple of the individual’s resting energy expenditure.
Confounding - Distortion in estimation of the association between two variables by a third variable.
Construct validity - The extent to which a method measures the theoretical construct it is designed to measure.
Content validity - The extent to which the method is considered to assess specific aspects of the phenomenon it is designed to assess.
Context - A dimension which describes environment aspects of physical activity. Describes variables such as where, who, when, why and in what conditions physical activity occurs.
Convergent validity - The extent to which predicted values match those derived from a comparison method, but one not generally accepted to be the gold-standard.
Criterion-related validity - The extent to which estimated values relate compare with those derived from a comparison or ‘criterion’ method, preferably one of very high validity and thought to provide the closest approximation of the true value, commonly referred to as a ‘gold-standard’ method.

D

Dietary biomarker - Any biological specimen that is an indicator of nutritional status with respect to intake or metabolism of dietary constituents. It can be biochemical, functional or clinical index of status of an essential nutrient or another dietary constituent.
Dietary pattern - The overall combination of foods habitually consumed.
Domain - A higher level classification for context of physical activity, and are part of this same dimension.
Duration - The time over which the physical activity takes place. This can vary from very short bouts of only a few seconds, to many hours of continuous activity.

E

Eating environment - External ambient factors present during eating, such as buildings, how food is obtained, the time of day, presence of others, or weather.
Exposure variable - The presumed cause in an observational study.
External validity - The degree to which a study sample is generalisable to other populations or settings.

F

Face Validity - The degree to which a method appears to provide the desired information about the variable it has been designed to measure.
Food composition database - Provide detailed information on the nutritional composition of foods.
Food composition tables - Printed versions of food composition databases.
Food - Any nutritious substance that is consumedin order to maintain life and growth.
Food group - A collection of foods that share similar nutritional properties or biological classifications.
Frequency - The number of occasions of activity in the given time frame (e.g. one day, one week, one year).

G

Generalisability - The extent to which findings can be applied to populations settings other than that in which they were originally examined.
Gold standard - A method with high validity which is suggested to provide estimated values closest to the true values for a specific variable.
Goldberg cut-off - Used to identify dietary underreporting and is based on the principle that an individual of a given age, sex and body weight requires a minimum energy intake.
Group level validity - The extent to which estimates for the group value (such as the mean or median) match the true group value.

H

Habitual diet - The typical diet of an individual that is relatively stable over time.
Heteroscedasticity - The circumstance in which the variability of a variable is unequal across the range of values of a second variable.
Homoscedasticity - The circumstance in which the variability of a variable is equal across the range of values of a second variable.

I

Individual level - The extent to which estimated values for individuals match the true individual values.
Inference - The process of deducing properties of an underlying distribution by analysis of data.
Information bias - The cumulative effect of errors introduced during data collection. Sub-types include observer bias, measurement bias and respondent bias.
Intensity - The rate of physical activity energy expenditure. The more intense the activity, the greater the metabolic cost per unit of time.
Internal consistency reliability - The extent to which items within a tool measure the same construct, or the consistency of a method across multiple applications within a single phase of a study. Commonly used in psychology, where multiple questions in a single questionnaire try to capture a single psychological ‘domain’ (e.g., temper).
Internal validity - The extent to which the study or estimate is free from bias or systematic error – i.e. the appropriateness and rigour of the study design, data collection protocols and/or analysis.
Inter-rater reliability - The similarity between data from different observers of the same phenomenon.
Instrument - The mechanism by which raw data are initially acquired, sometimes referred to as the ‘tool’.

J

K

L

Least sqaures regression - Mathematical model which finds the best-fitting curve to a given set of values by minimizing the sum of the squares of the differences (residuals) of those values from the curve.
Light intensity physical activity - Physical activity with intensity ≥1.5 METs and ˂ 3.0 METs.
Linear relationship - The condition where to variables are proportional to one another and if plotted on a scatter plot are best summarised by a straight line.

M

Micronutrient - A chemical element or substance required in trace amounts for normal growth and development.
Macronutrient - A chemical element or substance required in large amounts for normal growth and development.
Metabolic equivalent task (MET) - The intensity of physical activity expressed relative to an individual’s resting energy expenditure.
Method - The means by which raw data are first acquired using an instrument/tool, plus any data processing steps and use of additional data required to infer estimated values.
Moderate intensity physical activity - Physical activity with intensity ≥ 3.0 METs and ˂ 6.0 METs.
Moderate to vigorous physical activity (MVPA) - Physical activity intensity ≥ 3.0 METs.

N

Normal distribution - The arrangement of a data set in which the majority of values cluster around the mean and the rest taper off symmetrically toward either extreme.
Nutrient - A substance that provides nourishment essential for the maintenance of life and for growth.
Nutrition - The intake of food, considered in relation to the body’s dietary needs.
Nutritional requirement - The amount of each nutrient needed in the human body. Vary by individual.

O

Observer bias - A form of information bias in which the researcher’s knowledge of the study hypothesis or aims influences the measurement. For example, an interviewer placing emphasis or helping respondents with different questions.
Outcome variable - The presumed effect in an observational study.
Outlier - An extreme observation that appears to deviate markedly from other observations in a defined sample.

P

Physical activity (PA) - Any bodily movement produced by skeletal muscles resulting in energy expenditure.
Physical activity energy expenditure (PAEE) - The sum of energy expended due to physical activity during a specified time period. Also referred to as activity energy expenditure (AEE).
Physical activity level (PAL) - Total energy expenditure for 24 hours expressed as a multiple of basal energy expenditure.
Physical activity pattern - The variation of physical activity with time.
Physical inactivity - The condition in which an individual or group does not meet the recommended levels of physical activity. Not to be confused with sendetary behaviour.
Posture - Refers to the pose of the body.
Precision - The extent to which repeated application of a method produces values which are close together.

Q

R

Random error - Error which causes the estimated values to deviate from the true value due to chance alone, and is assumed to fluctuate above and below the true value by the same extent.
Reactivity bias - A form information bias which occurs when participants change their behaviour or performance because they are aware they are being observed.
Recall bias - A form of information bias caused by incomplete or inaccurate recollections of past events or experiences.
Relative reliability - The degree to which individuals maintain their position in a sample with replicate measurements using the same method.
Relative validity - The degree to which two methods, irrespective of units, rank individuals in the same order.
Reliability - The degree to which a method provides estimates that are stable or consistent, as opposed to erratic or variable.
Repeatability - The degree of variation in repeat measurements made of the same phenonemnon under identical conditions.
Reproducibility - The degree of variation in measurements made of the same phenomenon subject under changing conditions.
Residual confounding - The distortion that remains after controlling for confounding in the design and/or analysis of a study.
Respiratory exchange ratio (RER) - The ratio between the amount of carbon dioxide produced in metabolism and oxygen used. Also known as the respiratory quotient (RQ).
Resting energy expenditure (REE) - The sum of energy expenditure of an individual during rest. The largest component of total energy expenditure, including sleeping energy expenditure and the energy cost of wakefulness (sometimes termed arousal). Is normally slightly higher than basal metabolic energy expenditure (typically within 10%).
Resting metabolic rate (RMR) - The rate of energy expenditure of an individual at rest. Often measured in place of basal metabolic rate which requires strict conditions.

S

Sedentary Behaviour - Behaviour is defined as sedentary if it satisfies all of the following criteria: requires little or no energy expenditure (≤ 1.5 METs ); performed in a sitting or reclining posture; the individual is awake. Not to be confused with physical activity.
Selection Bias - Bias that occurs when the study sample is systematically unrepresentative of the target population about which conclusions are to be drawn.
Sleeping energy expenditure - The sum of energy expenditure during sleep.
Social desirability bias - A form of information bias which can cause over- or under-reporting of behaviours in order to appear favourable or avoid criticism.
Study sample - A subset of a population. Observations about the sample are used to infer characteristics of the population.
Study population - The collection of people, items, or events about which inferences are to be made.
Systematic error - Error which causes estimated values to deviate away from the true value in a particular direction.

T

Test-retest reliability The extent to which a method produces consistent data in similar conditions across multiple time points. Also known as stability.
Thermic effect of food (TEF) - Energy expenditure associated with the digestion, absorption and storage of food. Also referred to as dietary induced thermogenesis (DIT).
Tool - The mechanism by which raw data are initially acquired, sometimes referred to as the ‘instrument’.
Total energy expenditure (TEE) - The sum of all energy expended by an an indvidual during a specified time period (e.g. one day). Consists of basal energy expenditure, the thermic effect of food (TEF), and physical activity energy expenditure (PAEE).
Transformation - Application of a mathematical function to each point in a dataset, often to achieve a normal distribution or reduce the effect of outliers.
Truncation - Removal of values above or below an absolute (e.g. kcal/day) or relative threshold (mean ± three standard deviations).
Type - Describes the mode of human movement or the specific physical actions taking place.

U

V

Validity - The extent to which the estimated value matches the true value, or, the extent to which a method measures what it is supposed to measure.
Vigorous intensity physical activity - Physical activity intensity ≥ 6.0 METs.
Volume - The overall dose of physical activity in a given time frame (e.g. one day, one week, one year). The product of frequency, intensity and duration.

W

Winsorization - Recoding of extreme values to the nearest ‘reasonable’ values (either minimum or maximum).
Within-individual variation - The degree to which a characteristic changes for the same individual,. For example, minutes of walking and fruit consumption are both likely to vary from day-to-day.

X

Y

Z

DAPA Measurement Toolkit skip to primary navigation skip to content

Studying at Cambridge

DAPA Measurement Toolkit

Glossary

;

A

Absolute reliability - The agreement between replicate measures of the same phenomenon using the same method and units.
Absolute validity - The agreement between two methods measuring the same phenomenon with the same units.

B

Basal metabolic rate (BMR) - The rate of energy expenditure of an individual in a fasted state at complete rest the morning after sleep in a temperature neutral environment. This is the rate of energy expenditure required to maintain cellular functions.
Basal energy expenditure - The sum of energy expended by an individual in a fasted state at complete rest the morning after sleep in a temperature neutral environment during a specified time period. This is the energy expenditure required to maintain cellular functions.
Between-individual - The degree to which a characteristic is higher or lower for different people. For example, swimming participation and broccoli consumption likely differ by individual.
Bias - The cumulative effect of deviation of observations from truth.
Bioavailability - The proportion of nutrient in foods that are digested, absorbed and metabolised through normal pathways.

C

Compendium of physical activities - Activity cost table published by Ainsworth et al. (2011). Describes 821 activity types in terms their Metabolic Equivalent Task or MET , which is the multiple of the individual’s resting energy expenditure.
Confounding - Distortion in estimation of the association between two variables by a third variable.
Construct validity - The extent to which a method measures the theoretical construct it is designed to measure.
Content validity - The extent to which the method is considered to assess specific aspects of the phenomenon it is designed to assess.
Context - A dimension which describes environment aspects of physical activity. Describes variables such as where, who, when, why and in what conditions physical activity occurs.
Convergent validity - The extent to which predicted values match those derived from a comparison method, but one not generally accepted to be the gold-standard.
Criterion-related validity - The extent to which estimated values relate compare with those derived from a comparison or ‘criterion’ method, preferably one of very high validity and thought to provide the closest approximation of the true value, commonly referred to as a ‘gold-standard’ method.

D

Dietary biomarker - Any biological specimen that is an indicator of nutritional status with respect to intake or metabolism of dietary constituents. It can be biochemical, functional or clinical index of status of an essential nutrient or another dietary constituent.
Dietary pattern - The overall combination of foods habitually consumed.
Domain - A higher level classification for context of physical activity, and are part of this same dimension.
Duration - The time over which the physical activity takes place. This can vary from very short bouts of only a few seconds, to many hours of continuous activity.

E

Eating environment - External ambient factors present during eating, such as buildings, how food is obtained, the time of day, presence of others, or weather.
Exposure variable - The presumed cause in an observational study.
External validity - The degree to which a study sample is generalisable to other populations or settings.

F

Face Validity - The degree to which a method appears to provide the desired information about the variable it has been designed to measure.
Food composition database - Provide detailed information on the nutritional composition of foods.
Food composition tables - Printed versions of food composition databases.
Food - Any nutritious substance that is consumedin order to maintain life and growth.
Food group - A collection of foods that share similar nutritional properties or biological classifications.
Frequency - The number of occasions of activity in the given time frame (e.g. one day, one week, one year).

G

Generalisability - The extent to which findings can be applied to populations settings other than that in which they were originally examined.
Gold standard - A method with high validity which is suggested to provide estimated values closest to the true values for a specific variable.
Goldberg cut-off - Used to identify dietary underreporting and is based on the principle that an individual of a given age, sex and body weight requires a minimum energy intake.
Group level validity - The extent to which estimates for the group value (such as the mean or median) match the true group value.

H

Habitual diet - The typical diet of an individual that is relatively stable over time.
Heteroscedasticity - The circumstance in which the variability of a variable is unequal across the range of values of a second variable.
Homoscedasticity - The circumstance in which the variability of a variable is equal across the range of values of a second variable.

I

Individual level - The extent to which estimated values for individuals match the true individual values.
Inference - The process of deducing properties of an underlying distribution by analysis of data.
Information bias - The cumulative effect of errors introduced during data collection. Sub-types include observer bias, measurement bias and respondent bias.
Intensity - The rate of physical activity energy expenditure. The more intense the activity, the greater the metabolic cost per unit of time.
Internal consistency reliability - The extent to which items within a tool measure the same construct, or the consistency of a method across multiple applications within a single phase of a study. Commonly used in psychology, where multiple questions in a single questionnaire try to capture a single psychological ‘domain’ (e.g., temper).
Internal validity - The extent to which the study or estimate is free from bias or systematic error – i.e. the appropriateness and rigour of the study design, data collection protocols and/or analysis.
Inter-rater reliability - The similarity between data from different observers of the same phenomenon.
Instrument - The mechanism by which raw data are initially acquired, sometimes referred to as the ‘tool’.

J

K

L

Least sqaures regression - Mathematical model which finds the best-fitting curve to a given set of values by minimizing the sum of the squares of the differences (residuals) of those values from the curve.
Light intensity physical activity - Physical activity with intensity ≥1.5 METs and ˂ 3.0 METs.
Linear relationship - The condition where to variables are proportional to one another and if plotted on a scatter plot are best summarised by a straight line.

M

Micronutrient - A chemical element or substance required in trace amounts for normal growth and development.
Macronutrient - A chemical element or substance required in large amounts for normal growth and development.
Metabolic equivalent task (MET) - The intensity of physical activity expressed relative to an individual’s resting energy expenditure.
Method - The means by which raw data are first acquired using an instrument/tool, plus any data processing steps and use of additional data required to infer estimated values.
Moderate intensity physical activity - Physical activity with intensity ≥ 3.0 METs and ˂ 6.0 METs.
Moderate to vigorous physical activity (MVPA) - Physical activity intensity ≥ 3.0 METs.

N

Normal distribution - The arrangement of a data set in which the majority of values cluster around the mean and the rest taper off symmetrically toward either extreme.
Nutrient - A substance that provides nourishment essential for the maintenance of life and for growth.
Nutrition - The intake of food, considered in relation to the body’s dietary needs.
Nutritional requirement - The amount of each nutrient needed in the human body. Vary by individual.

O

Observer bias - A form of information bias in which the researcher’s knowledge of the study hypothesis or aims influences the measurement. For example, an interviewer placing emphasis or helping respondents with different questions.
Outcome variable - The presumed effect in an observational study.
Outlier - An extreme observation that appears to deviate markedly from other observations in a defined sample.

P

Physical activity (PA) - Any bodily movement produced by skeletal muscles resulting in energy expenditure.
Physical activity energy expenditure (PAEE) - The sum of energy expended due to physical activity during a specified time period. Also referred to as activity energy expenditure (AEE).
Physical activity level (PAL) - Total energy expenditure for 24 hours expressed as a multiple of basal energy expenditure.
Physical activity pattern - The variation of physical activity with time.
Physical inactivity - The condition in which an individual or group does not meet the recommended levels of physical activity. Not to be confused with sendetary behaviour.
Posture - Refers to the pose of the body.
Precision - The extent to which repeated application of a method produces values which are close together.

Q

R

Random error - Error which causes the estimated values to deviate from the true value due to chance alone, and is assumed to fluctuate above and below the true value by the same extent.
Reactivity bias - A form information bias which occurs when participants change their behaviour or performance because they are aware they are being observed.
Recall bias - A form of information bias caused by incomplete or inaccurate recollections of past events or experiences.
Relative reliability - The degree to which individuals maintain their position in a sample with replicate measurements using the same method.
Relative validity - The degree to which two methods, irrespective of units, rank individuals in the same order.
Reliability - The degree to which a method provides estimates that are stable or consistent, as opposed to erratic or variable.
Repeatability - The degree of variation in repeat measurements made of the same phenonemnon under identical conditions.
Reproducibility - The degree of variation in measurements made of the same phenomenon subject under changing conditions.
Residual confounding - The distortion that remains after controlling for confounding in the design and/or analysis of a study.
Respiratory exchange ratio (RER) - The ratio between the amount of carbon dioxide produced in metabolism and oxygen used. Also known as the respiratory quotient (RQ).
Resting energy expenditure (REE) - The sum of energy expenditure of an individual during rest. The largest component of total energy expenditure, including sleeping energy expenditure and the energy cost of wakefulness (sometimes termed arousal). Is normally slightly higher than basal metabolic energy expenditure (typically within 10%).
Resting metabolic rate (RMR) - The rate of energy expenditure of an individual at rest. Often measured in place of basal metabolic rate which requires strict conditions.

S

Sedentary Behaviour - Behaviour is defined as sedentary if it satisfies all of the following criteria: requires little or no energy expenditure (≤ 1.5 METs ); performed in a sitting or reclining posture; the individual is awake. Not to be confused with physical activity.
Selection Bias - Bias that occurs when the study sample is systematically unrepresentative of the target population about which conclusions are to be drawn.
Sleeping energy expenditure - The sum of energy expenditure during sleep.
Social desirability bias - A form of information bias which can cause over- or under-reporting of behaviours in order to appear favourable or avoid criticism.
Study sample - A subset of a population. Observations about the sample are used to infer characteristics of the population.
Study population - The collection of people, items, or events about which inferences are to be made.
Systematic error - Error which causes estimated values to deviate away from the true value in a particular direction.

T

Test-retest reliability The extent to which a method produces consistent data in similar conditions across multiple time points. Also known as stability.
Thermic effect of food (TEF) - Energy expenditure associated with the digestion, absorption and storage of food. Also referred to as dietary induced thermogenesis (DIT).
Tool - The mechanism by which raw data are initially acquired, sometimes referred to as the ‘instrument’.
Total energy expenditure (TEE) - The sum of all energy expended by an an indvidual during a specified time period (e.g. one day). Consists of basal energy expenditure, the thermic effect of food (TEF), and physical activity energy expenditure (PAEE).
Transformation - Application of a mathematical function to each point in a dataset, often to achieve a normal distribution or reduce the effect of outliers.
Truncation - Removal of values above or below an absolute (e.g. kcal/day) or relative threshold (mean ± three standard deviations).
Type - Describes the mode of human movement or the specific physical actions taking place.

U

V

Validity - The extent to which the estimated value matches the true value, or, the extent to which a method measures what it is supposed to measure.
Vigorous intensity physical activity - Physical activity intensity ≥ 6.0 METs.
Volume - The overall dose of physical activity in a given time frame (e.g. one day, one week, one year). The product of frequency, intensity and duration.

W

Winsorization - Recoding of extreme values to the nearest ‘reasonable’ values (either minimum or maximum).
Within-individual variation - The degree to which a characteristic changes for the same individual,. For example, minutes of walking and fruit consumption are both likely to vary from day-to-day.

X

Y

Z