Spatial Epi Concepts
Geographic Information Systems
Bias in Spatial Epi
Disease Mapping and Cluster Detection
Spatial Epi Surprise*
100
Non-causal association between and exposure and outcome observed as a result of the influence of a third variable.
What is confounding?
100
This type of spatial data represents the world as a grid of cells, and it is continuous in structure.
What is raster data?
100
Aggregating within polygons misses variation within
polygons leads to loss of variation and smoothes the data, which inflating standard errors and attenuates point estimates.
What is Aggregation Bias?
100
Spatial autocorrelation violates this fundamental statistical assumption required for standard regression models.
What is unit independence?
100
Developed by this psychologist, this theoretical model posits ecological systems theory of human
development, defined as “lasting change in the
way in which a person perceives and deals
with his environment.” It describes a sequence of nested ecological structures.
What is the Bronfenbrenner ecological model?
200
The core idea in routine activity theory is that crime happens when these three things come together at the same time and in the same place.
What is a motivated offender, a suitable target, and the absence of a capable guardian?
200
This vector feature has no area or length, only coordinates.
What is a point?
200
Occurs when researchers want to compare spatial data
with different geographies.
What is Spatial Misalignment?
200
This statistical measure tests whether cases are more clustered or dispersed in space than expected by chance.
What is Moran’s I (spatial autocorrelation)?
200
Distortions that arise from how subjects enter or exit a study.
What is selection bias?
300
The a)_____ is the entity on which data are recorded. The b)_____ is the entity at which you actually perform the statistical analysis and interpret the results.
what is a) the unit of observation and b) the unit of analysis?
300
A GIS operation that combines two datasets based on their geographic relationship.
What is spatial join?
300
This occurs when it is inferred that results based on aggregate zonal (or grouped) data can be applied to the individuals who form the zones or groups being studied.
What is ecological fallacy?
300
This is an example of a:
What is a Local Indicators of Spatial Autocorrelation (LISA)?
300
This first law is the foundation of the fundamental concepts of spatial dependence and spatial autocorrelation.
What is Tobler's First Law of Geography, which states: "everything is related to everything else, but near things are more related than distant things."
400
The application of theory and methods from epidemiology, geography, and statistics to describe spatial distributions of health outcomes and to analyze associations with possible causes to inform intervention and improve health.
What is spatial epidemiology?
400
This is best used for mid-latitude regions, such as the U.S. Distortion is often smallest along the standard parallels and becomes extreme near the poles and the equator.
What is a conic projection?
400
This concept refers to the distortion of statistical relationships when data is aggregated over different spatial areal units. Variations in results can often occur when spatial data for one set of areal units are progressively aggregated into fewer and/or larger units for analysis.
What is the Modifiable Areal Unit Problem (MAUP) Scale Effect?
400
A point-pattern analysis method used to test whether events are spatially clustered, dispersed, or randomly distributed across a range of distances.
What is Ripley’s K function?
400
This term describes abrupt policy or environmental changes that allow spatial epidemiologists to study their effects even though they were not randomly assigned.
What is a natural experiment?
500
If neighboring ZCTAs tend to have similarly high overdose rates, that is a)__________. If high-rate ZCTAs tend to sit next to low-rate ZCTAs, that is b)____________.
What are a) positive spatial autocorrelation and b) negative spatial autocorrelation?
500
Under the spatial science paradigm, this concept describes how we quantify relationships, test hypothesis, design our studies.
What is spatial statistics? (Going beyond the map!)
500
The basic problem is that a crude rate from a small area can be extremely noisy. For example, if one census tract has 2 overdoses among 500 people and another has 10 among 4,000, the rates look very different even though the difference may mostly reflect random variation. This method “pulls” those unstable estimates toward a more reliable value, usually based on the overall mean and/or neighboring areas.
What is spatial smoothing?
500
In an adjacency matrix, the a)_________, is when two polygons are considered neighbors if they share a border or a corner. The b)________ only counts polygons that share a border.
What is a) Queen's contiguity and b) Rook's contiguity?
500
Link and Phelan (1995) identify 3 conditions that may provide evidence of causation for observational studies.
What is:
–Natural experiments
–Where reverse causation is improbable (or not possible)
–Longitudinal studies demonstrate exposure primacy