Term
in this type of study subjects are chosen on the basis of exposure status and followed to assess the occurrence of disease 

Definition


Term
A special type of prospective cohort study in which investigators assign the exposure to individuals preferably at random 

Definition
experimental study option 


Term
cases with the disease and controls who generall do NOT have the disease are chosen and past exposure to a factor is determined is what type of study? 

Definition


Term
choice of study design depends on (4) 

Definition
state of knowledge frequency of exposure and dz time, cost, & feasability advantages & disadvantages 


Term
what 3 alternatives need to be RULED OUT in epidemiologic study? TEST ? 

Definition


Term
THE 2 QUESTIONS THAT MUST BE ASKED WHEN EVALUATING AN EPIDEMIOLOGIC STUDY? 

Definition
is the observed association CAUSAL? is the association VALID? 


Term
when assessing if the observed data in a study is valid you must do what three things? 

Definition
rule out random error (chance) rule out bias (systemic error) rule out confounding (mixing of effects) 


Term
P value and confidence intervals quantify what? 

Definition
the amount of random error 


Term
any systematic (non random) source of error in the determination of the association b/t the disease and exposure is what? 

Definition


Term
the type of bias that results in the selection of subjects 

Definition


Term
bias caused by how information was obtained? 

Definition


Term
a mixing of effects b/t the association of the disease, the exposure and a thired factor is what? 

Definition


Term
a group of people with a common characteristic like age, race, or sex? 

Definition


Term
the two types of population are based on whether the the membership is ?____ or _____ 

Definition


Term
in this type of population the membership is permanent and defined by an event? 

Definition


Term
in this type of population the membership is transient and defined by being in or out of a "state"? 

Definition


Term
an population of 5 YEAR cancer survivors is an example of what type of population? 

Definition


Term
THE RESIDENTS OF THE CITY OF SAVANNAH ar an example of what type of population? 

Definition
dynamic (because membership is transient) 


Term
measures of disease frequency should take three things into account? what are they? 

Definition
1. number of individuals affected with the 2. size of source population 3. length of time the population was followed 


Term
to measure the disease frequency of AIDS in two cities? what 3 things must be considered? 

Definition
1.# of new AIDS CASES 2.time period in which new AIDS cases occured 3.size of the source population the new AIDS cases arised. 


Term
the division of one number by another, (numbers dont have to be related) 

Definition


Term
the numerator is a subset of the denominator. (often expressed as a percentage) 

Definition


Term
time is an intrinsic part of the denominator (often most misused) 

Definition


Term
THE number of existing cases of a disease divided by the number in total population is what variable? 

Definition


Term
a city A has 7000 people with arthritis on Jan 1st 1999 & the population of city A is 70,000? what is the point prevalence (P) 

Definition


Term
THE number of NEW cases of disease that can occur more than once, usually initial occurence of disease? 

Definition


Term
what are the 2 types of incidence? 

Definition
incidence rate IR cumulative incidence CI 


Term
the number of new cases of disease divided by the number in candidate population over a specified period of time (during a specified time is what?) 

Definition


Term
10 cases of SIDS out of 1000 live births over 1 years time = a CI of ? 

Definition
10/1000= 1% cumulative incidence over 1 year 


Term
a cumulative incidence calculation assumes what_________________? 

Definition
that you have followed the entire population for the ENTIRE follow up period? 


Term
which type of incidence does not make assumption for complete follow up? 

Definition


Term
HE NUMBER OF NEW DISEASE DIVIDED BY THE PERSONTIME PERIOD OF OBSERVATION IN THE CANDIDATE POPULATION? 

Definition


Term
why is IR a measure of true rate? 

Definition
because it directly intergrates time into the denominator 


Term
ways to convert to person years (PY) 

Definition
100 people followed 1 yr each= 100py 10 people followed 10 yr each=100py 50people followed 1 yr + 25 people for 2 yr= 100py 


Term

Definition
# of cases / person time period 


Term

Definition
prevalence/ (1prevalence) 


Term
what can you conclude if: incidence is LOW but duration is long? 

Definition
prevalence is relatively high 


Term
if incidence is HIGH but duration is SHORT, you can conclude what? 

Definition
prevalence is relatively low 


Term
If the prevalence of a disease is low (<10%) the equation simplifies to ____? 

Definition


Term
the total number of deaths from all causes per standardized population per unit of time is what? 

Definition
crude death (mortality) rate 


Term
total number of live births per year standardized population denominator (e.g per 1000 women of childbearing age) 

Definition


Term
number of death in infants under 1 year of age per year divided by standardized population denominator (per 1000 live births) 

Definition


Term
# cases of disease that develop during defined time period divided by # in pop. at risk at start of period (usually used for infectious disease outbreaks) 

Definition


Term
# cases of disease that develop during defined time period divided by # in pop. at risk at start of period (usually used for infectious disease outbreaks) 

Definition


Term
# of deaths from a specific disease or disorder during a defined period of time divided by the # cases of disease / disorder 

Definition


Term
number of living cases of a disease / disorder for a defined period of time divided by the total number of cases of the disease / disorder 

Definition


Term
does the Overall rate of disease/outcome in an exposed group says nothing about whether exposure is a risk factor for or causes a disease or other outcome 

Definition


Term
the 2 main options for comparison groups are to calculate: 

Definition
1. the ratio 2. the difference 


Term
the rate/risk ratio is also known as the what? 

Definition


Term
what does the risk ratio compare? 

Definition
compares the disease occurence among exposed individuals to the comparison group which is usually unexposed 


Term
an RR (rate risk ratio of 1.0) tells you what? 

Definition
there is no association b/t exposure and disease 


Term
an RR (rate/risk ratio of 2.0) tells you what? 

Definition
there is two times the risk of dz in the exposed compared to the unexposed 


Term
what does a RR of 1.6 tell you? 

Definition
that there is a 1.6 times risk of dz in the exposed compared to the unexposed or 60% increased risk of disease in the exposed 


Term
difference measures are calculated by? 

Definition
Comparing disease occurrence among the exposed with the disease occurrence among the unexposed comparison group by subtracting one from the other 


Term
risk/rate difference is also known as ? 

Definition


Term
risk/rate difference is also known as ? 

Definition


Term
a rate/risk difference or attributable risk of 0 means what? 

Definition


Term

Definition
number of persons to treat to prevent one specific case of the disease or outcome of interest. 


Term
Diagnostic screening is only relevant under what 4 circumstances? 

Definition
1. if the dz is common 2. testing is sensitive,& specific 3. early tx improves outcomes 4. cost effectiv 


Term
the equation for TRUE POSITIVE RATE (TP) 

Definition


Term
THE PROBABILITY THAT A DISEASED INDIVIDUAL WILL BE IDENTIFIED AS SUCH BY THE TEST IS ? 

Definition


Term
THE PROBABILITY THAT AN INDIVIDUAL W/O THE DISEASE WILL BE IDENTIFIED AS SUCH IS ? 

Definition


Term

Definition


Term

Definition


Term
TO not "miss anyone" it is best to use cutoff points that__________ 

Definition
have increased sensitivity and decreased specificity 


Term
to make sure no member of the tested population is erroneously labled use test that have______________________ 

Definition
decreased (low) sensitivity and increased (higher) specificity 


Term
the positive and negative predictive values for a given test depend on what? 

Definition
the PRETEST PROBABILITY of the condition of interest as well as sen & specificity 


Term
positive predictive value eq: 

Definition


Term
NEGATIVE PREDICTIVE VALUE EQ: 

Definition


Term
ARE sensitivity and specificity altered by the pretest probability of the condition? 

Definition
NO, positive and negative predictive value are however altered 


Term
Likelihood ratio for a negative test = 

Definition
1sensitivity/ specificity 


Term
likelihood ratio for a positive test + 

Definition
sensitivity/1specificity 


Term
the 2 basic approaches to improve confirmatory accuracy in most cases are? 

Definition
1.parallel testing 2. serial testing 


Term
performing a PSA/DRE all at once is an example of what sort of testing? 

Definition
parallel testing (increases sensitivity and negative predicted values of results 


Term
what effect does serial testing have on test value results? 

Definition
serial test increase specificity and positive predicted value 


Term
what test increases sensitivity and negative predicted value 

Definition


Term
the earlier in a disease's natural hx it is detected, the longer will be the survival from the time of dx, even if there is no difference in tx effect defines what? 

Definition


Term
when screening detects dz that would have otherwise never become clinically detectable and remains stable and asymptomatic this is an example of ? 

Definition


Term
when cases are diagnosed by screening that may be destined for a more favorable evolution regardless of tx this describes what 

Definition

