ABATEMENT The process of reducing or minimizing public health dangers and nui- sances, usually supported by regulation or legislation; e.g., noise abatement, pollution ABC APPROACH"Abstinence, Be faithful, use Condoms. "ABC strategies are promoted to combat, foremost, infection with HIV and the HIVIAIDS pandemic as well as other sexually transmitted diseases. These are pragmatic sex education policies that aim at balancing abstinence-only sex education by including education about safe sex and birth control methods. Excessive emphasis on ABC strategies may marginalize broader, integrated programs in which all components are mutually reinforcing. See also CNN APPROACH ABORTION RATE The estimated annual number of abortions per 1000 women of repro- ductive age(usually defined as ages 15-44) ABORTION RATIO The estimated number of abortions per 100 live births in a given ABSCISSA The distance along the horizontal coordinate, or x axis, of a point P from the vertical or y axis of a graph. See also AXIS; GRAPH; ORDINATE. ABSOLUTE EFFECT The effect of an exposure(expressed as the difference between rates, proportions, means), of the outcome, etc, as opposed to the ratio of these meas ures.2 See also RISK DIFFERENCE ABSOLUTE POVERTY LEVEL Income level below which a minimum nutritionally adequate diet plus essential nonfood requirements is not affordable. The amount of income a person, family, or group needs to purchase an absolute amount of the basic necessities of life. See alSo RELATIVE POVERTY LEVEL ABSOLUTE RATE The number of specified health events(disease onset, death, etc.) divided by the time at risk in a defined population over a specified time interval. 2See also EvENt RATE: RATE RATIO. ABSOLUTE RISK(AR) The probability of an event(usually adverse, but it may also be beneficial) in the population under study. Contrast with RELATIVE RISK. The number of events in a group divided by the total number of subjects in that group. Sometimes AR is wrongly used as a synonym for ATTRIBUTABLE FRACTION; EXCESS RISK; OR RISK DIFFERENCE ABSOLUTE RISK INCREASE (ARI) The absolute risk of adverse events in the treat- ment group(ART) minus the absolute risk of events in the control group(ARC): ARI ART--ARC. Same as the RISK DIFFERENCE. Also, the proportion of treated persons
A ABATEMENT The process of reducing or minimizing public health dangers and nuisances, usually supported by regulation or legislation; e.g., noise abatement, pollution abatement. ABC APPROACH “Abstinence, Be faithful, use Condoms.” ABC strategies are promoted to combat, foremost, infection with HIV and the HIV/AIDS pandemic as well as other sexually transmitted diseases. These are pragmatic sex education policies that aim at balancing abstinence-only sex education by including education about safe sex and birth control methods. Excessive emphasis on ABC strategies may marginalize broader, integrated programs in which all components are mutually reinforcing. See also CNN approach. ABORTION RATE The estimated annual number of abortions per 1000 women of reproductive age (usually defi ned as ages 15–44). ABORTION RATIO The estimated number of abortions per 100 live births in a given year. ABSCISSA The distance along the horizontal coordinate, or x axis, of a point P from the vertical or y axis of a graph. See also axis; graph; ordinate. ABSOLUTE EFFECT The effect of an exposure (expressed as the difference between rates, proportions, means), of the outcome, etc., as opposed to the ratio of these measures.12 See also risk difference. ABSOLUTE POVERTY LEVEL Income level below which a minimum nutritionally adequate diet plus essential nonfood requirements is not affordable.13 The amount of income a person, family, or group needs to purchase an absolute amount of the basic necessities of life. See also relative poverty level. ABSOLUTE RATE The number of specifi ed health events (disease onset, death, etc.) divided by the time at risk in a defi ned population over a specifi ed time interval.12 See also event rate; rate ratio. ABSOLUTE RISK (AR) The probability of an event (usually adverse, but it may also be benefi cial) in the population under study. Contrast with relative risk. The number of events in a group divided by the total number of subjects in that group. Sometimes AR is wrongly used as a synonym for attributable fraction; excess risk; or risk difference. ABSOLUTE RISK INCREASE (ARI) The absolute risk of adverse events in the treatment group (ART) minus the absolute risk of events in the control group (ARC): ARI = ART—ARC. Same as the risk difference. Also, the proportion of treated persons 1
Absolute risk reduction(ARR) who experience an adverse event minus the proportion of untreated persons who experience the event. See also NUMBER NEEDED TO HARM(NNH) ABSOLUTE RISK REDUCTION (ARR) 1. The arithmetic difference between two event rates. The amount by which the risk of an undesirable event is reduced by elimination or control of a particular exposure. It enables an estimate of the number of people spared the consequences of an 2. The absolute risk of events in the control group(ARC) minus the absolute risk of events in the treatment group(ArT): ARR=ARC-ART The negative of the RISK DIFFERENCE.Also, the proportion of untreated persons who experience an adverse event minus the proportion of treated persons who experience this event. The reciprocal of the ARR is the NUMBER NEEDED TO TREAT(NNT). The ARR is one measure of the strength of an association. It varies with the underlying risk of an event e.g., it becomes smaller when EVENT RATES are low. The ARR is higher and the nNt lower in groups with higher absolute risks. 4,I5 See also EVENT RATE; HILLS CRITERIA OF CAUSATION, MEASURE OF ASSOCIATION, PROBABILITY OF CAUSATION, RELATTVE RISK REDUCTION ACCEPTABLE RISK Risk that appears tolerable to some group Risk that has minimal or long-term detrimental effects or for which the benefits outweigh the potential haz ards. epidemiological CH has provided data for calculation of risks increased by many medical procedures as well as by occupational and environmental exposures these data are used. for instance. in clinical DECISION aNaLySIS and HEALTh technolOGY ASSESSMENT ACCEPTANCE SAMPLING(Syn: stop-or-go sampling) Sampling method that requires division of the"universe " population into groups or batches as they pass a specified time point(e.g, age), followed by sampling of individuals within the sampled groups ACCIDENT An unanticipated event--commonly leading to INJURY or other harm--in traffic, the workplace, or a domestic or recreational setting. The primary event in sequence that leads ultimately to injury if that event is genuinely not predictable. Epi- demiological studies have demonstrated that the risk of accidents is often predictable accidents are preventable. This word is preferably avoided in many types of ACCUMULATION OF RISK The extent of cumulative damage to biological systems as he number, duration, or severity of exposures increases and as body systems age and become less able to repair damage. The notion that LIFE COURSE exposures or insults gradually accumulate through episodes of illness and injury, adverse environmental conditions, and health damaging behaviors. Exposures increasing risk of disease may be independent or clustered; in the latter case an accumulation model with risk clustering is used. 6 See also DEVELOPMENTAL AND LIFE COURSE EPIDEMIOLOGY: THRIFTY PHENOTYPI HYPOTHESIS ACCURACY 1. The degree to which a measurement or an estimate based on measurements presents the true value of the attribute that is being measured. Relative lack of ERROR. See also MEASUREMENT TERMINOLOGY OF: VALIDITY. STI The ability of a diagnostic test to correctly classify the presence or absence of the target disorder. The diagnostic accuracy of a test is usually expressed by its SENSITIVITY
who experience an adverse event minus the proportion of untreated persons who experience the event. See also number needed to harm (NNH). ABSOLUTE RISK REDUCTION (ARR) 1. The arithmetic difference between two event rates. The amount by which the risk of an undesirable event is reduced by elimination or control of a particular exposure. It enables an estimate of the number of people spared the consequences of an exposure. 2. The absolute risk of events in the control group (ARC) minus the absolute risk of events in the treatment group (ART): ARR = ARC—ART. The negative of the risk difference. Also, the proportion of untreated persons who experience an adverse event minus the proportion of treated persons who experience this event. The reciprocal of the ARR is the number needed to treat (NNT). The ARR is one measure of the strength of an association. It varies with the underlying risk of an event; e.g., it becomes smaller when event rates are low. The ARR is higher and the NNT lower in groups with higher absolute risks.14, 15 See also event rate; Hill’s criteria of causation; measure of association; probability of causation; relative risk reduction. ACCEPTABLE RISK Risk that appears tolerable to some group. Risk that has minimal or long-term detrimental effects or for which the benefi ts outweigh the potential hazards. Epidemiological research has provided data for calculation of risks increased by many medical procedures as well as by occupational and environmental exposures; these data are used, for instance, in clinical decision analysis and health technology assessment. ACCEPTANCE SAMPLING (Syn: stop-or-go sampling) Sampling method that requires division of the “universe” population into groups or batches as they pass a specifi ed time point (e.g., age), followed by sampling of individuals within the sampled groups. ACCIDENT An unanticipated event—commonly leading to injury or other harm—in traffi c, the workplace, or a domestic or recreational setting. The primary event in a sequence that leads ultimately to injury if that event is genuinely not predictable. Epidemiological studies have demonstrated that the risk of accidents is often predictable and that accidents are preventable. This word is preferably avoided in many types of scientifi c works. ACCUMULATION OF RISK The extent of cumulative damage to biological systems as the number, duration, or severity of exposures increases and as body systems age and become less able to repair damage. The notion that life course exposures or insults gradually accumulate through episodes of illness and injury, adverse environmental conditions, and health damaging behaviors. Exposures increasing risk of disease may be independent or clustered; in the latter case an accumulation model with risk clustering is used.16 See also developmental and life course epidemiology; thrifty phenotype hypothesis. ACCURACY 1. The degree to which a measurement or an estimate based on measurements represents the true value of the attribute that is being measured. Relative lack of error. See also measurement, terminology of; validity, study. 2. The ability of a diagnostic test to correctly classify the presence or absence of the target disorder. The diagnostic accuracy of a test is usually expressed by its sensitivity and specifi city. Absolute risk reduction (ARR) 2
3 ACE American College of Epidemiology ACQUAINTANCE NETWORK A group of persons in contact or communication among whom transmission of an infectious agent and of knowledge, behavior, and values is possible and whose social interaction may have health implications. See also CoNTEXT, TRANSMISSION OF INFECTION ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS)(Syn: acquired immune defi ciency syndrome) The late clinical stage of infection with HUMAN IMMUNODEFICIENCY VIRUS(HIV), recognized as a distinct syndrome in 1981. The opportunistic or indica tor diseases associated with AIDs include certain protozoan and helminth infections, fungal infections, bacterial infections, viral infections, and some types of cancer. The role of aids as an indicator in surveillance has diminished since the advent of HIGHLY ACTIVE ANTIRETROVIRAL THERAPY(HAART). See also HUMAN IMMUNODEFICIENCY ACTIVE LIFE EXPECTANCY See DISABILITY-FREE LIFE EXPECTANCY. ACTIVITIES OF DAILY LIVING(ADL)SCALE A scale devised by Katz and others 7 to score physical ability/disability; used to measure outcomes of interventions for various chronic, disabling conditions, such as arthritis. The scale is based on scores for responses to ques- tions about mobility, self-care, grooming, etc. This was the first widely used scale of this type others, mostly refinements or variations of the ADL scale, have since been developed ACTIVITY SETTING The places, events, routines, and patterns that structure the experi- nce of everyday life: e.g., a classroom, a neighborhood resident meeting, a commuter train, family meals, a waiting room in a hospital. The unit by which culture and commu- nity are propagated across time. See also BEHAVIOR SETTING; CONTEXT ACTUARIAL RATE See FORCE OF MORTALITY ACTUARIAL TABLE See LiFE TABLE 1. Referring to a health effect: sudden onset, often brief; sometimes loosely used to mean severe Referring to an exposure: brief, intense, or short-term; sometimes specifically referring to a brief exposure of high intensity. See also CHRONIC. ADAPTATION I. The process by which organisms surmount environmental challenges. See also 2. A heritable component of the phenotype that confers an advantage in survival and reproductive success. ADDITIVE MODEL A model in which the combined effect on the risks or rates of several factors is the sum of the effects that would be produced by each of the factors in the absence of the others. For example, if factor X adds x to risk in the absence of y and actor Y adds y to risk in the absence of X, an additive model states that the two factors together will add(r+y)to risk. See also INTERACTION; LINEAR MODEL; MATHEMATICA ODEL, MULTIPLICATIVE MODEL. ADELF Association des Epidemiologists de Langue Francaise(Association of Epidemi- logists of French Language) ADHERENCE Health-related behavior that adheres to the recommendations of a doctor other health care provider, or investigator in a research project. The word adherence aims to avoid the authoritarian associations of COMPLIANCE, formerly used to describe this behavior. Concordance is another alternative to compliance. 9
ACE American College of Epidemiology. ACQUAINTANCE NETWORK A group of persons in contact or communication among whom transmission of an infectious agent and of knowledge, behavior, and values is possible and whose social interaction may have health implications. See also context; transmission of infection. ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS) (Syn: acquired immune defi - ciency syndrome) The late clinical stage of infection with human immunodefi ciency virus (HIV), recognized as a distinct syndrome in 1981. The opportunistic or indicator diseases associated with AIDS include certain protozoan and helminth infections, fungal infections, bacterial infections, viral infections, and some types of cancer. The role of AIDS as an indicator in surveillance has diminished since the advent of highly active antiretroviral therapy (HAART). See also human immunodefi ciency virus (hiv). ACTIVE LIFE EXPECTANCY See disability-free life expectancy. ACTIVITIES OF DAILY LIVING (ADL) SCALE A scale devised by Katz and others17 to score physical ability/disability; used to measure outcomes of interventions for various chronic, disabling conditions, such as arthritis. The scale is based on scores for responses to questions about mobility, self-care, grooming, etc. This was the fi rst widely used scale of this type; others, mostly refi nements or variations of the ADL scale, have since been developed. ACTIVITY SETTING The places, events, routines, and patterns that structure the experience of everyday life; e.g., a classroom, a neighborhood resident meeting, a commuter train, family meals, a waiting room in a hospital. The unit by which culture and community are propagated across time.18 See also behavior setting; context. ACTUARIAL RATE See force of mortality. ACTUARIAL TABLE See life table. ACUTE 1. Referring to a health effect: sudden onset, often brief; sometimes loosely used to mean severe. 2. Referring to an exposure: brief, intense, or short-term; sometimes specifi cally referring to a brief exposure of high intensity. See also chronic. ADAPTATION 1. The process by which organisms surmount environmental challenges. See also resilience. 2. A heritable component of the phenotype that confers an advantage in survival and reproductive success. ADDITIVE MODEL A model in which the combined effect on the risks or rates of several factors is the sum of the effects that would be produced by each of the factors in the absence of the others. For example, if factor X adds x to risk in the absence of Y and factor Y adds y to risk in the absence of X, an additive model states that the two factors together will add (x + y) to risk. See also interaction; linear model; mathematical model; multiplicative model. ADELF Association des Épidémiologistes de Langue Française (Association of Epidemiologists of French Language). ADHERENCE Health-related behavior that adheres to the recommendations of a doctor, other health care provider, or investigator in a research project. The word adherence aims to avoid the authoritarian associations of compliance, formerly used to describe this behavior. Concordance is another alternative to compliance. 19 3 Adherence
Adjustment ADJUSTMENT A summarizing procedure for a statistical measure in which the effects of differences in composition of the populations being compared have been minimized by statistical methods. Examples are adjustment by regression analysis, by inverse-probability weighting, and by standardization. Adjustment is often performed on a rate or on an EFFECT MEASURE, commonly because of differing age and sex distributions in the populations being compared. The mathematical procedure commonly used to adjust rates for age differences is( direct or indirect) ADULT LITERACY RATE The percentage of persons 15 years of age and over who can ADVERSE REACTION An undesirable or unwanted consequence of a preventive, diag nostic, or therapeutic procedure. See also SIDE EFFECT. AES American Epidemiological Society AETIOLOGY. AETIoLOGICAL See etiolOGY AGE The WHO recommends that age should be defined by completed units of time, ounting the day of birth as zero. AGE DEPENDENCY RATIO See DEPENDENCY RATIO AGENT (OF DISEASE) A factor-such as a microorganism, chemical substance, or form of radiation--whose presence, excessive presence, or (in deficiency diseases) relative absence is essential for the occurrence of a disease. a disease may have a single agent,a number of independent alternative agents(at least one of which must be present ),or a complex of two or more factors whose combined presence is essential for the develop- ment of the disease. See alSo CAUSALITY NECESSARY CAUSE AGE-PERIOD COHORT ANALYSIS See COHORT ANALYSIS AGE-SEX PYRAMID See POPULATION PYRAMID AGE-SEX REGISTER A list of all clients or patients of a medical practice or service, classified by age(birthdate)and sex; it provides denominators for calculating age-and ex-specific rates. AGE-SPECIFIC FERTILITY RATE The number of live births occurring during a specified period to women of a specified age group divided by the number of person-years lived during that period by women of that age group. When an age-specific fertility rate is calculated for a calendar year, the number of live births to women of the specified age usually divided by the midyear population of women of that age. AGE-SPECIFIC RATE A rate for a specified age group. The numerator and denominator refer to the same age group Age-specific death rate [age(25-34)1= age 25-34 in an area in a ye 100.000 average(for midyear) population age 25-34 in the area in that year The multiplier (usually 100,000 or 1 million) is chosen to produce a rate that can be expressed as a convenient number. AGE STANDARDIZATION A procedure for adjusting rates(e. g, death rates)designed to minimize the effects of differences in age composition in comparing rates for different populations. ee alSo ADJUSTMENT: STANDARDIZATION
ADJUSTMENT A summarizing procedure for a statistical measure in which the effects of differences in composition of the populations being compared have been minimized by statistical methods.20 Examples are adjustment by regression analysis, by inverse-probability weighting, and by standardization. Adjustment is often performed on a rate or on an effect measure, commonly because of differing age and sex distributions in the populations being compared. The mathematical procedure commonly used to adjust rates for age differences is (direct or indirect) standardization. ADULT LITERACY RATE The percentage of persons 15 years of age and over who can read and write.21 ADVERSE REACTION An undesirable or unwanted consequence of a preventive, diagnostic, or therapeutic procedure. See also side effect. AES American Epidemiological Society. AETIOLOGY, AETIOLOGICAL See etiology. AGE The WHO recommends that age should be defi ned by completed units of time, counting the day of birth as zero. AGE DEPENDENCY RATIO See dependency ratio. AGENT (OF DISEASE) A factor—such as a microorganism, chemical substance, or form of radiation—whose presence, excessive presence, or (in defi ciency diseases) relative absence is essential for the occurrence of a disease. A disease may have a single agent, a number of independent alternative agents (at least one of which must be present), or a complex of two or more factors whose combined presence is essential for the development of the disease. See also causality; necessary cause. AGE-PERIOD COHORT ANALYSIS See cohort analysis. AGE-SEX PYRAMID See population pyramid. AGE-SEX REGISTER A list of all clients or patients of a medical practice or service, classifi ed by age (birthdate) and sex; it provides denominators for calculating age- and sex-specifi c rates. AGE-SPECIFIC FERTILITY RATE The number of live births occurring during a specifi ed period to women of a specifi ed age group divided by the number of person-years lived during that period by women of that age group. When an age-specifi c fertility rate is calculated for a calendar year, the number of live births to women of the specifi ed age is usually divided by the midyear population of women of that age. AGE-SPECIFIC RATE A rate for a specifi ed age group. The numerator and denominator refer to the same age group. Example: number of deaths among residents age 25–34 in an area in a year Age-specifi c death rate [age (25–34)] = ———————––––––––————— × 100,000 average (for midyear) population age 25–34 in the area in that year The multiplier (usually 100,000 or 1 million) is chosen to produce a rate that can be expressed as a convenient number. AGE STANDARDIZATION A procedure for adjusting rates (e.g., death rates) designed to minimize the effects of differences in age composition in comparing rates for different populations. See also adjustment; standardization. Adjustment 4
AGGREGATION BIAS(Syn: ecological bias) See AGGREGATIVE FALLACY; ECOLOGICAL AGGREGATE SURVEILLANCE The surveillance of a disease or health event by collect- ing summary data on groups of cases(e.g, general practitioners taking part in surveil lance schemes are asked to report the number of cases of specified diseases seen over a specified period of time) AGGREGATIVE FALLACY An erroneous application to individuals of a causal relation- ship observed at the group level. A type of ECOLOGICAL FALLACY(sometimes just a syno- nym)and an antonym AGING OF THE POPULATION An increase over time in the proportion of older person in a defined population. It does not necessarily imply an increase in life expectancy or that people are living longer than they used to. In the past, the principal cause of aging of populations has been a de the birth rate: in the absence of a rise in the death rate at higher ages, when fewer children are born than in prior years, the proportion of older persons in the population increases. Nowadays, in developed societies, little fur- ther mortality reduction can occur in the first parts of life; thus, reductions in mortality that occur in the third and fourth quarters of life are leading to a rise in the proportion of older persons. See also DEMOGRAPHICTRANSITION AIRBORNE INFECTION An infection whose agent is transmitted by particles, dust, or DROPLET NUCLEI suspended in the air. The infective agent may be transmitted by a patient or carrier in airborne droplets expelled during coughing and sneezing. See also TRANSMISSION OF INFECTION ALGORITHM Any systematic process that consists of an ordered sequence of steps with each step depending on the outcome of the previous one. The term is commonly used to describe a structured processfor instance, relating to computer programming or health planning. See also DECISION TREE. ALGORITHM, CLINICAL(Syn: clinical protocol) An explicit description of steps to be taken in patient care in specified circumstances. This approach makes use of branching logic and of all pertinent data, both about the patient and from epidemio- logical and other sources, to arrive at decisions that yield maximum benefit and ALLELE Alternative forms of a gene occupying the same locus on a chromosome. Each of the different states found at a polymorphic site.23 ALLOCATION BIAS An error in the estimate of an effect caused by failure to implement valid procedures for random allocation of subjects to intervention and control groups n a CLINICAL TRIAL ALLOCATION CONCEALMENT A method of generating a sequence that ensures ran dom allocation between two or more arms of a study without revealing this to study ubjects or researchers. The quality of allocation concealment is enhanced by compu ter-based random allocation and other procedures to make the process impervious to ALLOCATION BIAS. See also BLIND(ED)STUDY; RANDOM ALLOCATION ALMA-ATA DECLARATION See HEALTH CARE: HEALTH FOR ALL, PRIMARY HEALTH CARE. ALPHA ERROR See ERROR TYPE L. AMBIENT Surrounding: pertaining to the environment in which events are observed AMES TEST A BIOASSAY for mutagenesis, using bacteria as target, to detect and screen for potentially CARCINOGENIc compounds Developed from the early 1970s by Bruce Ames and colleagues at the University of California, Berkeley. See CARCINOGEN
AGGREGATION BIAS (Syn: ecological bias) See aggregative fallacy; ecological fallacy; atomistic fallacy. AGGREGATE SURVEILLANCE The surveillance of a disease or health event by collecting summary data on groups of cases (e.g., general practitioners taking part in surveillance schemes are asked to report the number of cases of specifi ed diseases seen over a specifi ed period of time). AGGREGATIVE FALLACY An erroneous application to individuals of a causal relationship observed at the group level. A type of ecological fallacy (sometimes just a synonym) and an antonym of the atomistic fallacy. 22 AGING OF THE POPULATION An increase over time in the proportion of older persons in a defi ned population. It does not necessarily imply an increase in life expectancy or that people are living longer than they used to. In the past, the principal cause of aging of populations has been a decline in the birth rate: in the absence of a rise in the death rate at higher ages, when fewer children are born than in prior years, the proportion of older persons in the population increases. Nowadays, in developed societies, little further mortality reduction can occur in the fi rst parts of life; thus, reductions in mortality that occur in the third and fourth quarters of life are leading to a rise in the proportion of older persons. See also demographic transition. AIRBORNE INFECTION An infection whose agent is transmitted by particles, dust, or droplet nuclei suspended in the air. The infective agent may be transmitted by a patient or carrier in airborne droplets expelled during coughing and sneezing. See also transmission of infection. ALGORITHM Any systematic process that consists of an ordered sequence of steps with each step depending on the outcome of the previous one. The term is commonly used to describe a structured process—for instance, relating to computer programming or health planning. See also decision tree. ALGORITHM, CLINICAL (Syn: clinical protocol) An explicit description of steps to be taken in patient care in specifi ed circumstances. This approach makes use of branching logic and of all pertinent data, both about the patient and from epidemiological and other sources, to arrive at decisions that yield maximum benefi t and minimum risk. ALLELE Alternative forms of a gene occupying the same locus on a chromosome. Each of the different states found at a polymorphic site.23 ALLOCATION BIAS An error in the estimate of an effect caused by failure to implement valid procedures for random allocation of subjects to intervention and control groups in a clinical trial. ALLOCATION CONCEALMENT A method of generating a sequence that ensures random allocation between two or more arms of a study without revealing this to study subjects or researchers. The quality of allocation concealment is enhanced by computer-based random allocation and other procedures to make the process impervious to allocation bias. See also blind(ed) study; random allocation. ALMA-ATA DECLARATION See health care; health for all; primary health care. ALPHA ERROR See error, type i. AMBIENT Surrounding; pertaining to the environment in which events are observed. AMES TEST A bioassay for mutagenesis, using bacteria as target, to detect and screen for potentially carcinogenic compounds. Developed from the early 1970s by Bruce Ames and colleagues at the University of California, Berkeley. See carcinogen. 5 Ames test