Sander Greenland
Biographic Data
| ID | 1837244 |
|---|---|
| NAME | Sander Greenland |
| GIVEN NAMES | Sander |
| FAMILY NAME | Greenland |
| SIGNATURE | GREENLAND S |
| AFFILIATIONS | University of California, Los Angeles |
| ORCID | 0000-0003-4364-3279 |
| VERIFIED | Yes |
| TOTAL WORKS | 34 |
| TOTAL CITATIONS | 177 |
| AUTHOR COUNT | 34 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1979 |
| LATEST PUBLICATION YEAR | 2024 |
| H-INDEX | 5 |
Forcing a Deterministic Frame on Probabilistic Phenomena
The current controversy surrounding research replication in biomedical and psychosocial sciences often overlooks the uncertainties surrounding both the original and replication studies. Overemphasizing single attempts as definitive replication successes or failures, as exemplified by media coverage of the landmark Reproducibility Project: Psychology, fosters misleading dichotomies and erodes public trust. To avoid such unintended consequences, sc…
Understanding and reporting odds ratios as rate-ratio estimates in case-control studies
Background: We noted that there remains some confusion in the health-science literature on reporting sample odds ratios as estimated rate ratios in case-control studies. Methods: We recap historical literature that definitively answered the question of when sample odds ratios (ORs) from a case-control study are consistent estimators for population rate ratios. We use numerical examples to illustrate the magnitude of the disparity between sample O…
Accurate Statistics on Covid-19 Are Essential for Policy Guidance and Decisions
Disease surveillance forms the basis for response to epidemics. COVID-19 provides a modern example of why the classic mantra of “person, place, and time” remains crucial: epidemic control requires
Scientists rise up against statistical significance
Remove, rather than redefine, statistical significance
Statistical tests, P values, confidence intervals, and power
Misinterpretation and abuse of statistical tests, confidence intervals, and statistical power have been decried for decades, yet remain rampant. A key problem is that there are no interpretations of these concepts that are at once simple, intuitive, correct, and foolproof. Instead, correct use and interpretation of these statistics requires an attention to detail which seems to tax the patience of working scientists. This high cognitive demand ha…
The Table 2 Fallacy
It is common to present multiple adjusted effect estimates from a single model in a single table. For example, a table might show odds ratios for one or more exposures and also for several confounders from a single logistic regression. This can lead to mistaken interpretations of these estimates. We use causal diagrams to display the sources of the problems. Presentation of exposure and confounder effect estimates from a single model may lead to …
Transparency and disclosure, neutrality and balance
Values influence choice of methodology and thus influence every risk assessment and inference. To deal with this inescapable reality, we need to replace vague and unattainable calls for objectivity with more precise operational qualities. Among qualities that seem widely valued are transparency (openness) and neutrality (balance, fairness). Conformity of researchers to these qualities may be evaluated by considering whether their reports disclose…
Plenary VI all inference is biased judgement
One of the most pernicious myths perpetrated by standard methodologic training is that of unbiased or objective inference. Unbiased inference exists only within highly simplified models that do not begin to reflect the complexities of genuine public-health and risk-assessment settings. In those settings, neither unbiased estimators nor unbiased judgements can be identified. All inferences depend on biased judgements, albeit some judgements are hi…
Prevalence and clustering of metabolic risk factors for type 2 diabetes among Chinese adults in Shanghai, China
These data indicate that multiple metabolic risk factors--individually or jointly--were more prevalent in diabetes patients than in controls. Further research will examine hypotheses concerning the high prevalence of IFG, family history, and central obesity, aiding development of multifaceted preventive strategies specific to this population
Accounting for uncertainty about investigator bias
Biasing of studies towards results desired by the investigators—investigator bias—arises from many sources, from outright data fabrication to subtle and even unconscious bias in design and analysis choices. Investigator bias has had an important impact in some areas of clinical practice, and can be a major source of uncertainty about study effects. Among the sources of investigator bias, empirical studies have suggested that estimates of effect a…
Age of minority sexual orientation development and risk of childhood maltreatment and suicide attempts in women
Women with minority sexual orientations (e.g., lesbian, bisexual) are more likely than heterosexual women to report histories of childhood maltreatment and attempted suicide; however, the importance of the timing of minority sexual orientation development in contributing to this increased risk is uncertain. This study investigated relationships between self-reported ages of achieving minority sexual orientation development milestones (first aware…
Uncertainty analysis
Uncertainty analysis is a method, established in engineering and policy analysis but relatively new to epidemiology, for the quantitative assessment of biases in the results of epidemiological studies. Each uncertainty analysis is situation specific, but usually involves four main steps: (1) specify the target parameter of interest and an equation for its estimator; (2) specify the equation for random and bias effects on the estimator; (3) specif…
Associations of Maternal Age- and Parity-Related Factors With Trends in Low-Birthweight Rates
Objectives. We assessed the effects of changes in the maternal age–parity distribution and age-and parity-specific low-birthweight rates on low-birthweight trends in the United States. Methods. We used natality file data from 1980 through 2000 to assess very-low-birthweight and low-birthweight rates among singleton live-born infants. Results. Changes in age-and parity-specific low-birthweight rates were the main contributor to the overall trend i…
Yang Et Al. Respond
We thank Schempf and Becker for pointing out a deficiency in our presentation, although we disagree with their solution. In fact, we were aware of the alternative standards they cite and rejected them as inappropriate. Although researchers are often taught otherwise, the choice of standard distributions is not arbitrary and should not be based on symmetry or other mathematical considerations. Rather, the choice of standard distribution should be …
Causation and Causal Inference in Epidemiology
Concepts of cause and causal inference are largely self-taught from early learning experiences. A model of causation that describes causes in terms of sufficient causes and their component causes illuminates important principles such as multicausality, the dependence of the strength of component causes on the prevalence of complementary component causes, and interaction between component causes. Philosophers agree that causal propositions cannot …
Model-based Estimation of Relative Risks and Other Epidemiologic Measures in Studies of Common Outcomes and in Case-Control Studies
Some recent articles have discussed biased methods for estimating risk ratios from adjusted odds ratios when the outcome is common, and the problem of setting confidence limits for risk ratios. These articles have overlooked the extensive literature on valid estimation of risks, risk ratios, and risk differences from logistic and other models, including methods that remain valid when the outcome is common, and methods for risk and rate estimation…
Associations of Race/Ethnicity With HIV Prevalence and HIV-Related Behaviors Among Young Men Who Have Sex With Men in 7 Urban Centers in the United States
Using data from a multisite venue-based survey of male subjects aged 15 to 22 years, we examined racial/ethnic differences in demographics, partner type, partner type-specific condom use, drug use, and HIV prevalence in 3316 US black, multiethnic black, Latino, and white men who have sex with men (MSM). We further estimated associations of these factors with HIV infection and their influence on racial/ethnic disparities in HIV prevalence. HIV pre…
Risk Factors, Confounding, and the Illusion of Statistical Control
When experimental designs are premature, impractical, or impossible, researchers must rely on statistical methods to adjust for potentially confounding effects. Such procedures, however, are quite fallible. We examine several errors that often follow the use of statistical adjustment. The first is inferring a factor is causal because it predicts an outcome even after "statistical control" for other factors. This inference is fallacious when (as u…
Quantifying Biases in Causal Models
It has long been known that stratifying on variables affected by the study exposure can create selection bias. More recently it has been shown that stratifying on a variable that precedes exposure and disease can induce confounding, even if there is no confounding in the unstratified (crude) estimate. This paper examines the relative magnitudes of these biases under some simple causal models in which the stratification variable is graphically dep…
HIV Prevalence Among Foreign- and US-Born Clients of Public STD Clinics
Objectives. We examined differences in HIV seroprevalence and the likely timing of HIV infection by birth region. Methods. We analyzed unlinked HIV antibody data on 61 120 specimens from 7 public health centers in Los Angeles County from 1993 to 1999. Results. Most (87%) immigrant clients were Central American/Mexican–born. HIV prevalence was similar for US- and foreign-born clients (1.8% [95% confidence interval (CI) = 1.7%, 1.9%] and 1.6% [95% …
Causal Diagrams for Epidemiologic Research
Causal diagrams have a long history of informal use and, more recently, have undergone formal development for applications in expert systems and robotics. We provide an introduction to these developments and their use in epidemiologic research. Causal diagrams can provide a starting point for identifying variables that must be measured and controlled to obtain unconfounded effect estimates. They also provide a method for critical evaluation of tr…
Relation of probability of causation to relative risk and doubling dose
Epidemiologists, biostatisticians, and health physicists frequently serve as expert consultants to lawyers, courts, and administrators. One of the most common errors committed by experts is to equate, without qualification, the attributable fraction estimated from epidemiologic data to the probability of causation requested by courts and administrators. This error has become so pervasive that it has been incorporated into judicial precedents and …
Basic Methods for Sensitivity Analysis of Biases
Most discussions of statistical methods focus on accounting for measured confounders and random errors in the data-generating process. In observational epidemiology, however, controllable confounding and random error are sometimes only a fraction of the total error, and are rarely if ever the only important source of uncertainty. Potential biases due to unmeasured confounders, classification errors, and selection bias need to be addressed in any …
Simulation Study of Confounder-Selection Strategies
In the absence of prior knowledge about population relations, investigators frequently employ a strategy that uses the data to help them decide whether to adjust for a variable. The authors compared the performance of several such strategies for fitting multiplicative Poisson regression models to cohort data: 1) the "change-in-estimate" strategy, in which a variable is controlled if the adjusted and unadjusted estimates differ by some important a…
Modeling and variable selection in epidemiologic analysis
This paper provides an overview of problems in multivariate modeling of epidemiologic data, and examines some proposed solutions. Special attention is given to the task of model selection, which involves selection of the model form, selection of the variables to enter the model, and selection of the form of these variables in the model. Several conclusions are drawn, among them: a) model and variable forms should be selected based on regression d…
Basic Methods for Sensitivity Analysis of Biases
Most discussions of statistical methods focus on accounting for measured confounders and random errors in the data-generating process. In observational epidemiology, however, controllable confounding and random error are sometimes only a fraction of the total error, and are rarely if ever the only important source of uncertainty. Potential biases due to unmeasured confounders, classification errors, and selection bias need to be addressed in any …
Causation and Causal Inference in Epidemiology
Concepts of cause and causal inference are largely self-taught from early learning experiences. A model of causation that describes causes in terms of sufficient causes and their component causes illuminates important principles such as multicausality, the dependence of the strength of component causes on the prevalence of complementary component causes, and interaction between component causes. Philosophers agree that causal propositions cannot …
Accurate Statistics on Covid-19 Are Essential for Policy Guidance and Decisions
Disease surveillance forms the basis for response to epidemics. COVID-19 provides a modern example of why the classic mantra of “person, place, and time” remains crucial: epidemic control requires
HIV Prevalence Among Foreign- and US-Born Clients of Public STD Clinics
Objectives. We examined differences in HIV seroprevalence and the likely timing of HIV infection by birth region. Methods. We analyzed unlinked HIV antibody data on 61 120 specimens from 7 public health centers in Los Angeles County from 1993 to 1999. Results. Most (87%) immigrant clients were Central American/Mexican–born. HIV prevalence was similar for US- and foreign-born clients (1.8% [95% confidence interval (CI) = 1.7%, 1.9%] and 1.6% [95% …
Age of minority sexual orientation development and risk of childhood maltreatment and suicide attempts in women
Women with minority sexual orientations (e.g., lesbian, bisexual) are more likely than heterosexual women to report histories of childhood maltreatment and attempted suicide; however, the importance of the timing of minority sexual orientation development in contributing to this increased risk is uncertain. This study investigated relationships between self-reported ages of achieving minority sexual orientation development milestones (first aware…
Associations of Maternal Age- and Parity-Related Factors With Trends in Low-Birthweight Rates
Objectives. We assessed the effects of changes in the maternal age–parity distribution and age-and parity-specific low-birthweight rates on low-birthweight trends in the United States. Methods. We used natality file data from 1980 through 2000 to assess very-low-birthweight and low-birthweight rates among singleton live-born infants. Results. Changes in age-and parity-specific low-birthweight rates were the main contributor to the overall trend i…
Relation of probability of causation to relative risk and doubling dose
Epidemiologists, biostatisticians, and health physicists frequently serve as expert consultants to lawyers, courts, and administrators. One of the most common errors committed by experts is to equate, without qualification, the attributable fraction estimated from epidemiologic data to the probability of causation requested by courts and administrators. This error has become so pervasive that it has been incorporated into judicial precedents and …
Remove, rather than redefine, statistical significance
Accounting for uncertainty about investigator bias
Biasing of studies towards results desired by the investigators—investigator bias—arises from many sources, from outright data fabrication to subtle and even unconscious bias in design and analysis choices. Investigator bias has had an important impact in some areas of clinical practice, and can be a major source of uncertainty about study effects. Among the sources of investigator bias, empirical studies have suggested that estimates of effect a…
Forcing a Deterministic Frame on Probabilistic Phenomena
The current controversy surrounding research replication in biomedical and psychosocial sciences often overlooks the uncertainties surrounding both the original and replication studies. Overemphasizing single attempts as definitive replication successes or failures, as exemplified by media coverage of the landmark Reproducibility Project: Psychology, fosters misleading dichotomies and erodes public trust. To avoid such unintended consequences, sc…
Transparency and disclosure, neutrality and balance
Values influence choice of methodology and thus influence every risk assessment and inference. To deal with this inescapable reality, we need to replace vague and unattainable calls for objectivity with more precise operational qualities. Among qualities that seem widely valued are transparency (openness) and neutrality (balance, fairness). Conformity of researchers to these qualities may be evaluated by considering whether their reports disclose…
Uncertainty analysis
Uncertainty analysis is a method, established in engineering and policy analysis but relatively new to epidemiology, for the quantitative assessment of biases in the results of epidemiological studies. Each uncertainty analysis is situation specific, but usually involves four main steps: (1) specify the target parameter of interest and an equation for its estimator; (2) specify the equation for random and bias effects on the estimator; (3) specif…
Effectiveness of the Cavity-Rim Cervical Cap
From 1981-1988, 3433 women were fitted with a cavity-rim cervical cap in a Food and Drug Administration-approved study. The estimated first-year pregnancy risk was 11.3% (95% confidence limits 10.0-12.8), with risks of 8.3 and 3.8% for user and method failures, respectively. Women who were younger, less educated, and more sexually active, and who intended to have children in the future, had higher pregnancy risks. Near-perfect users, ie, individu…
Vaccine failures in the epidemiology and control of measles
Data were employed from confirmed measles case reports and an immunization survey to estimate the apparent effectiveness of measles vaccine in Los Angeles County in 1976. We evaluated the age-specific proportions of our case load arising from persons erroneously thought to possess immunity. Thirty five per cent of our cases claimed to have had prior measles vaccination, and over 60 per cent of these reported having written records. Since communit…
The Case-Control Method in Medical Care Evaluation
The case-control method has been applied extensively to the study of chronic diseases, largely because of its advantage in cost and statistical power over other study designs. However, problems in ensuring the validity of case-control results have led to certain reservations regarding the general utility of the method. We discuss how several of the major validity problems in case-control studies of chronic disease are limited or absent in case-co…
Morgenstern Corrects a Conceptual Error
Morgenstern Corrects a Conceptual Error Sander Greenland, and Hal Morgenstern CopyRight https://doi.org/10.2105/AJPH.73.6.703-a Published Online: October 07, 2011
Ecological Bias, Confounding, and Effect Modification
Greenland S (Division of Epidemiology, UCLA School of Public Health, Los Angeles, California 90024, USA) and Morgenstern H. Ecological bias, confounding, and effect modification. International Journal of Epidemiology 1989, 18: 269–274. Ecological bias is sometimes attributed to confounding by the group variable (ie the variable used to define the ecological groups), or to risk factors associated with the group variable. We show that the group var…
The Impact of Confounder Selection Criteria on Effect Estimation
Mickey, R. M. (Dept of Mathematics and Statistics, U. of Vermont, Burlington, VT 05405) and S. Greenland. The impact of confounder selection criteria on effect estimation. Am J Epidemiol 1989;129:125–37. Much controversy exists regarding proper methods for the selection of variables in confounder control. Many authors condemn any use of significance testing, some encourage such testing, and others propose a mixed approach. This paper presents the…
Modeling and variable selection in epidemiologic analysis
This paper provides an overview of problems in multivariate modeling of epidemiologic data, and examines some proposed solutions. Special attention is given to the task of model selection, which involves selection of the model form, selection of the variables to enter the model, and selection of the form of these variables in the model. Several conclusions are drawn, among them: a) model and variable forms should be selected based on regression d…
Effectiveness of the Cavity-Rim Cervical Cap
From 1981-1988, 3433 women were fitted with a cavity-rim cervical cap in a Food and Drug Administration-approved study. The estimated first-year pregnancy risk was 11.3% (95% confidence limits 10.0-12.8), with risks of 8.3 and 3.8% for user and method failures, respectively. Women who were younger, less educated, and more sexually active, and who intended to have children in the future, had higher pregnancy risks. Near-perfect users, ie, individu…
Letters on Epidemiologic Research Methods
Letters on Epidemiologic Research Methods I. `Occurrence Rates' for Disease Charles Poole, Stephan F. Lanes, Faith Davis, Neil Pearce, Aaron J. Cohen, Stuart L. Shalat, David A. Savitz, Hal Morgenstern, and Sander Greenland Alvan R. Feinstein, Charles K. Chan, John M. Esdaile, Michael J. McFarlane, and Carolyn K. Wells CopyRight https://doi.org/10.2105/AJPH.80.5.622 Published Online: October 07, 2011
Identifiability and Exchangeability for Direct and Indirect Effects
We consider the problem of separating the direct effects of an exposure from effects relayed through an intermediate variable (indirect effects). We show that adjustment for the intermediate variable, which is the most common method of estimating direct effects, can be biased. We also show that even in a randomized crossover trial of exposure, direct and indirect effects cannot be separated without special assumptions; in other words, direct and …
Simulation Study of Confounder-Selection Strategies
In the absence of prior knowledge about population relations, investigators frequently employ a strategy that uses the data to help them decide whether to adjust for a variable. The authors compared the performance of several such strategies for fitting multiplicative Poisson regression models to cohort data: 1) the "change-in-estimate" strategy, in which a variable is controlled if the adjusted and unadjusted estimates differ by some important a…
Basic Methods for Sensitivity Analysis of Biases
Most discussions of statistical methods focus on accounting for measured confounders and random errors in the data-generating process. In observational epidemiology, however, controllable confounding and random error are sometimes only a fraction of the total error, and are rarely if ever the only important source of uncertainty. Potential biases due to unmeasured confounders, classification errors, and selection bias need to be addressed in any …
Causal Diagrams for Epidemiologic Research
Causal diagrams have a long history of informal use and, more recently, have undergone formal development for applications in expert systems and robotics. We provide an introduction to these developments and their use in epidemiologic research. Causal diagrams can provide a starting point for identifying variables that must be measured and controlled to obtain unconfounded effect estimates. They also provide a method for critical evaluation of tr…
Relation of probability of causation to relative risk and doubling dose
Epidemiologists, biostatisticians, and health physicists frequently serve as expert consultants to lawyers, courts, and administrators. One of the most common errors committed by experts is to equate, without qualification, the attributable fraction estimated from epidemiologic data to the probability of causation requested by courts and administrators. This error has become so pervasive that it has been incorporated into judicial precedents and …
HIV Prevalence Among Foreign- and US-Born Clients of Public STD Clinics
Objectives. We examined differences in HIV seroprevalence and the likely timing of HIV infection by birth region. Methods. We analyzed unlinked HIV antibody data on 61 120 specimens from 7 public health centers in Los Angeles County from 1993 to 1999. Results. Most (87%) immigrant clients were Central American/Mexican–born. HIV prevalence was similar for US- and foreign-born clients (1.8% [95% confidence interval (CI) = 1.7%, 1.9%] and 1.6% [95% …
Quantifying Biases in Causal Models
It has long been known that stratifying on variables affected by the study exposure can create selection bias. More recently it has been shown that stratifying on a variable that precedes exposure and disease can induce confounding, even if there is no confounding in the unstratified (crude) estimate. This paper examines the relative magnitudes of these biases under some simple causal models in which the stratification variable is graphically dep…
Model-based Estimation of Relative Risks and Other Epidemiologic Measures in Studies of Common Outcomes and in Case-Control Studies
Some recent articles have discussed biased methods for estimating risk ratios from adjusted odds ratios when the outcome is common, and the problem of setting confidence limits for risk ratios. These articles have overlooked the extensive literature on valid estimation of risks, risk ratios, and risk differences from logistic and other models, including methods that remain valid when the outcome is common, and methods for risk and rate estimation…
Associations of Race/Ethnicity With HIV Prevalence and HIV-Related Behaviors Among Young Men Who Have Sex With Men in 7 Urban Centers in the United States
Using data from a multisite venue-based survey of male subjects aged 15 to 22 years, we examined racial/ethnic differences in demographics, partner type, partner type-specific condom use, drug use, and HIV prevalence in 3316 US black, multiethnic black, Latino, and white men who have sex with men (MSM). We further estimated associations of these factors with HIV infection and their influence on racial/ethnic disparities in HIV prevalence. HIV pre…
Risk Factors, Confounding, and the Illusion of Statistical Control
When experimental designs are premature, impractical, or impossible, researchers must rely on statistical methods to adjust for potentially confounding effects. Such procedures, however, are quite fallible. We examine several errors that often follow the use of statistical adjustment. The first is inferring a factor is causal because it predicts an outcome even after "statistical control" for other factors. This inference is fallacious when (as u…
Causation and Causal Inference in Epidemiology
Concepts of cause and causal inference are largely self-taught from early learning experiences. A model of causation that describes causes in terms of sufficient causes and their component causes illuminates important principles such as multicausality, the dependence of the strength of component causes on the prevalence of complementary component causes, and interaction between component causes. Philosophers agree that causal propositions cannot …
Associations of Maternal Age- and Parity-Related Factors With Trends in Low-Birthweight Rates
Objectives. We assessed the effects of changes in the maternal age–parity distribution and age-and parity-specific low-birthweight rates on low-birthweight trends in the United States. Methods. We used natality file data from 1980 through 2000 to assess very-low-birthweight and low-birthweight rates among singleton live-born infants. Results. Changes in age-and parity-specific low-birthweight rates were the main contributor to the overall trend i…
Yang Et Al. Respond
We thank Schempf and Becker for pointing out a deficiency in our presentation, although we disagree with their solution. In fact, we were aware of the alternative standards they cite and rejected them as inappropriate. Although researchers are often taught otherwise, the choice of standard distributions is not arbitrary and should not be based on symmetry or other mathematical considerations. Rather, the choice of standard distribution should be …
Uncertainty analysis
Uncertainty analysis is a method, established in engineering and policy analysis but relatively new to epidemiology, for the quantitative assessment of biases in the results of epidemiological studies. Each uncertainty analysis is situation specific, but usually involves four main steps: (1) specify the target parameter of interest and an equation for its estimator; (2) specify the equation for random and bias effects on the estimator; (3) specif…
Accounting for uncertainty about investigator bias
Biasing of studies towards results desired by the investigators—investigator bias—arises from many sources, from outright data fabrication to subtle and even unconscious bias in design and analysis choices. Investigator bias has had an important impact in some areas of clinical practice, and can be a major source of uncertainty about study effects. Among the sources of investigator bias, empirical studies have suggested that estimates of effect a…
Age of minority sexual orientation development and risk of childhood maltreatment and suicide attempts in women
Women with minority sexual orientations (e.g., lesbian, bisexual) are more likely than heterosexual women to report histories of childhood maltreatment and attempted suicide; however, the importance of the timing of minority sexual orientation development in contributing to this increased risk is uncertain. This study investigated relationships between self-reported ages of achieving minority sexual orientation development milestones (first aware…
Prevalence and clustering of metabolic risk factors for type 2 diabetes among Chinese adults in Shanghai, China
These data indicate that multiple metabolic risk factors--individually or jointly--were more prevalent in diabetes patients than in controls. Further research will examine hypotheses concerning the high prevalence of IFG, family history, and central obesity, aiding development of multifaceted preventive strategies specific to this population
Medicine (21 works) · Mathematics (15 works) · Statistics (15 works) · Advanced Causal Inference Techniques (13 works) · Econometrics (12 works) · Computer Science (11 works) · Confounding (9 works) · Psychology (8 works) · Demography (7 works) · Meta-analysis and systematic reviews (7 works)