Lecture 10

Question 1

Internal validity

Answer 1

the degree to which a study can confidently establish a cause-and-effect relationship between the exposure and the outcome within the specific context of the study

Question 2

What do well-designed experiments enable us to demonstrate?

Answer 2

how manipulating one set of
variables produces systematic changes in another set of variables

Question 3

Descriptive research

Answer 3

gather info about phenomena

Question 4

Causal research

Answer 4

what are the causes of illness and disability

Question 5

Causal research is the basis of what?

Answer 5

the basis to formulate and justify our assessments, diagnoses, and interventions

Question 6

Criteria for demonstrating causal associations: the _______ must precede the _______

Answer 6

cause
effect

Question 7

Criteria for demonstrating causal associations: the cause and effect ________. If the ______ occurs, then so does the _______

Answer 7

covary
cause
effect

Question 8

Criteria for demonstrating causal associations: if the cause ______ occur the effect ______ occur

Answer 8

does not
does not

Question 9

What does causality in research mean

Answer 9

establishing lawful functional relationship between cause and effect

Question 10

In scientific research, understanding causality isn’t just about observing that one thing influences another—it’s about being able to do what?

Answer 10

control the cause so you can reproduce or change the effect at will

Question 11

Causality researchers describe what, and then do what?

Answer 11

patterns/co-variations and then formulate hypothesis or theory for cause

Question 12

Causality researchers attempt eliminate what?

Answer 12

alternative explanations or hypotheses for cause

Question 13

Threats to internal validity

Answer 13

Factors that can provide alternative explanations for the observed results in a study, thereby compromising the ability to confidently conclude that the treatment (or intervention) caused the observed outcomes

Question 14

8 threats to internal validity

Answer 14

history
maturation
testing
instrumentation
selection errors
regression to the mean
attrition
placebo effect

Question 15

Threats to internal validity: history

Answer 15

Events or experiences occurring between the pretest and post-test that are outside the control of the study and may affect the outcome

Question 16

Threats to internal validity: maturation

Answer 16

Internal changes within participants that occur
naturally over time, independent of the treatment or intervention

Question 17

Threats to internal validity: testing

Answer 17

the effect that repeated testing can have on
participants. Pre-tests may influence how participants
behave in the post-test

Question 18

Threats to internal validity: instrumentation

Answer 18

Changes in the measurement tools or
methods used between pre-test and post-test that can affect the results

Question 19

Threats to internal validity: selection/assignment

Answer 19

Differences between groups at baseline

Question 20

Threats to internal validity: regression to the mean

Answer 20

occurs when participants are selected based on extreme scores and when measured again, their scores tend to move closer to the average

Question 21

Threats to internal validity: attrition

Answer 21

Dropout; occurs when participants drop out of the study at different rates across groups, and those who drop out may differ
significantly from those who stay

Question 22

Threats to internal validity: placebo effect

Answer 22

occurs when participants experience changes in their
condition simply because they believe they are receiving a treatment,
even if the treatment has no therapeutic effect

Question 23

How do researchers ensure internal validity

Answer 23

must control for the effects of confounding and bias

Question 24

In nutrition research controlling _________ can be more difficult

Answer 24

confounders

Question 25

Randomizing in experimental designs is key to what?

Answer 25

equalizing confounding factors between intervention and control groups

Question 26

Blinding helps reduce _____, particularly when it comes to _______ or ________

Answer 26

bias placebo effects observer bias

Question 27

What do control groups allow for?

Answer 27

the comparison of outcomes in those receiving the treatment versus those not receiving it, isolating the effect of the intervention

Question 28

True or false: the control group does not undergo the same conditions as the treatment group

Answer 28

false - they do undergo the same conditions

Question 29

Improvements may occur even if the treatment or intervention is ________ and ________ inert

Answer 29

physiologically chemically

Question 30

What does the control group allow the researcher to measure

Answer 30

the size of the placebo effect, and to take it into account when interpreting the study results

Question 31

Control is a matter of _______, not ____ or ____

Answer 31

degree on or off

Question 32

Studies that have high internal validity often involve what?

Answer 32

tightly controlled experimental conditions

Question 33

Lower external validity: the controlled environment may not reflect what

Answer 33

real-world settings

Question 34

Controlled environment may not reflect real-world settings making it harder to do what?

Answer 34

to generalize the findings to broader populations or different contexts

Question 35

Do studies conducted in naturalistic or real-world settings have higher or lower external validity

Answer 35

higher

Question 36

Why do studies conducted in naturalistic or real-world settings have higher validity

Answer 36

because they involve participants in their usual environments and behaviors

Question 37

Naturalistic setting studies may lack what?

Answer 37

control over confounding factors

Question 38

Lack of control over confounding factors in naturalistic settings make what difficult?

Answer 38

determining causal relationships clearly