Ch. 11: Reasoning About the Design and Execution of Research Flashcards
defn: the scientific method
a set of steps that define the appropriate order of events to structure and carry out an experiment
the established protocol for transitioning from a question to a new body of knowledge
what are the 8 steps of the scientific method?
- generate a testable question
- gather data and resources
- form a hypothesis
- collect new data
- analyze the data
- interpret the data and existing hypothesis
- publish
- verify results
explain why step 1 of scientific method (generate a testable question) happens?
usually occurs after observing something anomalous in another scientific inquiry or in daily life
defn: hypothesis
the proposed explanation or proposed answer to our testable question
often in the form of an if-then statement
defn: experimentation vs. observation
experimentation: involves manipulating and controlling variables of interest
observation: often involves no changes in the subject’s environment
explain: step 6 of the scientific method (interpret the data and existing hypothesis)
consider whether the data analysis is consistent with the original hypothesis
if the data is inconsistent, consider alternative hypotheses
explain: step 8 of the scientific method (verify results)
most experiments are repeated to verify the results under new conditions
most questions that begin with what word are too broad to be testable through a single experiment?
WHY
what does the if-then format of a hypothesis ensure?
that it is testable
func + defn: FINER method
for evaluating a research question
a method to determine whether the answer to one’s question will add to the body of scientific knowledge ini a practical way and within a reasonable time period
what are the 5 questions of the FINER method?
- Is the necessary research study going to be FEASIBLE?
- Do other scientists find this question INTERESTING?
- Is this particular question NOVEL?
- Would the study obey ETHICAL principles?
- Is the question RELEVANT outside the scientific community?
what are 4 feasibility concerns that we consider in the FINER method?
- obtaining necessary supplies
- financial constraints
- time constraints
- the inability to gather enough subjects
what is the reason for controls in basic science research?
we use controls because in order to make generalizations about our experiments, we must make sure that the outcome of interest would not have occurred without our intervention
aka: control
standard
defn: positive controls + example
those that ensure a change in the dependent variable when it is expected
example: in the development of a new assay for detection of HIV, administering the test to a group of blood samples known to contain HIV could constitute a positive control
defn: negative controls + example
ensure no change in the dependent variable when no change is expected
example: the same assay as above, administering the test to a group of blood samples known NOT to contain HIV could constitute a negative control
what is a negative control group often used for in drug trials?
to assess for the placebo effect
defn: placebo effect
an observed or reported change when an individual is given a sugar pill or sham intervention
do we manipulate or measure/observe the independent or dependent variable?
MANIPULATE: independent variable
MEASURE/OBSERVE: dependent variable
what is another big advantage to being able to manipulate all of the relevant experimental conditions?
basic scientific researchers can often establish causality
what relationship must there be between independent and dependent variables for causality to be investigated?
when there is a theoretical or known mechanism that links the independent and dependent variables
what relationship must there be between independent and dependent variables for causality to claimed?
if the change in the independent variable always precedes the change in the dependent variable, and the change in the dependent variable does not occur in the absence of the experimental intervention
there is minimal experimental bias in basic science research, but what are three ways that bias can appear?
- generation of a faulty hypothesis from incomplete early data and resource collection
- eliminating trials without appropriate background
- failing to publish works that contradict the experimenter’s own hypothesis
defn: accuracy (+aka) vs. precision (+aka)
ACCURACY = validity = the ability of an instrument to measure a true value
PRECISION = reliability = the ability of the instrument to read consistently or within a narrow range
explain the difference between accuracy and precision by describing a person weighing themselves on a scale
170 lb person
ACCURATE but IMPRECISE scale = readings between 150-190 lbs
INACCURATE but PRECISE scale = readings between 129-131 lbs
will an inaccurate or imprecise tool introduce bias or error? why?
bias is a SYSTEMATIC ERROR
so only an INACCURATE tool will introduce bias, but an IMPRECISE tool will still introduce error
defn: random error
error introduced by random chance
how do we avoid random error?
usually overcome by a large sample size
defn: randomization
the method used to control for differences between subject groups in biomedical research
uses an algorithm to determine the placement of each subject into either a control group that receives no treatment or a sham treatment or one or more treatment groups
what will a proper randomization algorithm be equal to?
a coin toss or die roll
defn + func: blinded
the subjects and/or investigators do not have information about which group the subject is in
to remove bias
defn: single-blind experiments
only the patient or the assessor is blinded
defn: assessor
the person who makes measurements on the patient or performs subjective evaluations
defn: double-blind experiments
the investigator, subject, and assessor all do not know the subject’s group
how does the placebo effect differ between the control and treatment group WITHOUT blinding?
WITHOUT blinding, the placebo effect would be greatly reduced in the control group, but still be present in the treatment group