Analytical vs. Descriptive Studies Flashcards

Question

If RR is close to 1 what does that mean?

Answer 1

The exposure is probably not associated with the risk of the dz

Answer 2

the exposure is likey to be associated with the risk of dz

Answer 3

The stronger the association between the risk & the dz.

Answer 4

Relative Risk =_ Incidence in the exposed_ Incidence in the unexposed RR= 1, NO ASSOCIATION RR \> 1, (+) association, possibly causal RR \< 1, (-) association, possibly protective

Answer 5

Confidence intervals

Answer 6

a measure of the reliability of an estimate.

Answer 7

If the 95% CI **DOES NOT** include the null value of 1, but falls entirely on either side of it

Answer 8

* measure incidence * **describe temporal relationships** * Can collect data on possible confounders (age, sex, breed, etc)

Answer 9

* Useful when exposure is rare * can examine the multiple likely outcomes/dz of a single exposure

Answer 10

* Inefficient for rare diseases * requires good records * may lack data on confounders * selection bias

Answer 11

* Expensive & long * large number of subjects are needed * loss to follow-up which can affect validity

Answer 12

* Cases & controls are selected * compare the frequency of exposure factors in the cases w/ that of the controls

Answer 13

those study subjects who have developed the dz of interest

Answer 14

* study subjects who have not developed the dz of interest at the time of selection Key point: represent individuals whose exposure to the factor of interest reflects the exposure in the population from which cases were selected

Answer 15

* Select a dz * get a case definition * have diagnostic criteria

Answer 16

* should be similar cases * should be identical to cases in every respect except the dz of interest * "match" controls to cases on possible confounders (age, breed, sex)

Answer 17

Odds Ratio | (interpret as you would the RR)

Answer 18

* **Efficient for rare diseases** or when long interval btwn exposure & dz. * **able to evaulate multiple etiologies** * inexpensive & fast * **require relatively small number of subjects**

Answer 19

* cannot directly estimate incidence or prevalence * selection of controls can be difficult * recall bias from owner * **temporal relationships between exposure & occurrence of dz are difficult to establish**

Answer 20

test the effect of new TX/prevention intervention

Answer 21

Clinical trails (intervention studies)

Answer 22

* less opportunity for error * animals randomly allocated to avoid bias * measure the effect of a TX/prevention intervention after a certain time

Answer 23

Prevention Trials | (Field trial)

Answer 24

use blinding to eliminate selcetion & observation bias

Answer 25

* Open * Blinded * Double-blinded

Answer 26

subject & investigator know who is assigned to which treatment group

Answer 27

investigator knows but subjects are blind to TX assignment

Answer 28

Subject and investigators are blind to TX assigned

Answer 29

* What were TXs compared to * were individuals randomly allocated * was double-blinding performed * Were withdrawals from the study reported * Stastical significane & power

Answer 30

* Phase I - product safety is tested on a limited # of animals * Phase II - limited # of animals are vaccinated & then challenged * Phase III - large # of animals are vaccinated to estimate both efficacy & effectiveness of vaccine

Answer 31

* researcher has control * **best measure of causal relationship** * provides cause-effect data * randomized - less confounding & removes selection bias * Blinding - eliminates selection & observation bias

Answer 32

* excessive control does not mean it accurately represents the real situation * requires a large sample size * costly * long duration * ethical consideration * bias may be introduced

Answer 33

* Study randomized? * Double-blinded? * Follow up \> 80%? * Was the study question answered? * How large was the TX effect? * Will results help my patient? * Were study patients similar to yours? * Are the benefits wortht the risk & cost?