Observations And Measurements/experiments

Front 1

What is it to "make an observation"?

Back 1

General observations are comprised of three steps:

Generation: The object of interest together with the circumstances of observation cause an observable/detectable event/property.
Detection & Collection

Interpretation

Front 2

In what two ways can observations be said to be theory dependent?

Back 2

Taking an observable property to be an indicator of a feature of interest is in itself an hypothesis or assumption about the feature of interest.
Observation of operationalized properties is in this sense theory dependent.
Theoretical commitments exert a strong influence on observation descriptions.

Front 3

What is confirmation bias?

Back 3

Collection of evidence: Search for evidence that can confirm your hypothesis

Interpretation of evidence: The observer "sees" what he/she expects to see

Front 4

What two problems does on try to solve by double-blinding medical tests?

Back 4

Both reducing the effect of placebo and the effect of observer/pediatritian expectations.

Front 5

What do you do when you "operationalize" a property?

Back 5

To operationalize a feature of interest is to provide a way of linking it to observable properties.

Front 6

What two criteria should a good operationalization satisfy?

Back 6

1. Avoid interpretation and analysis.

2. Construct validity. Check that the operationalization reflects the feature of interest.

Front 7

What is a measurement scale?

Back 7

• Scales provide a more exact way of
representing features of interest.
• They provide a more exact language in
which observations can be described and
communicated.

Front 8

What does one mean by a systematic versus a random error?

Back 8

If a measuring instrument tends to yield either too high values in most measurements or
too low values in most measurements, then there is a systematic error - this can be corrected for by calibration.

A random error is randomly distributed between too low and too high values.

Front 9

What is the difference between a reliable versus a valid method of measurement?

Back 9

Reliable: high degree of reliability - low degree of random error

Valid: low systematic error and high convergent and divergent validity

Front 10

What do you do when you calibrate an instrument?

Back 10

Adjust the instrument to give on average the correct value, usually by using well-known sources.

Front 11

In what ways can the numbers of Celcius scale be said to be "merely conventional" (arbitrary); in what ways not?

Back 11

The fixed reference points (0 and 100 degrees) are arbitrary. However the choice of equal intervals is a mathematical and physical necessity in order for it to be useful as a scientific measuring scale.

Front 12

What is the Likert scale? Should it be considered an interval scale? Why does it matter?

Back 12

1. Strongly disagree - 5. Strongly agree.

It is only an interval scale if the difference between e.g. 2-3 is the same as 4-5. Not necessarily so that two units -> double agreement.

Important to keep that in mind for average calculations.

Front 13

What distinguishes natural experiments from field experiments?

Back 13

Nat. exp.: features are naturally arranged in such a fashion as if they were controlled by an experiment (e.g. two similar islands)

Field exp.: Observation of a set of features over a period of time or over a population for a defined time.

Front 14

What distinguishes simulation experiments from laboratory experiments?

Back 14

Sim. exp.: Same as lab.exp but on a representation instead. Can be closly related to modelling or even laboratory experiments (e.g. lab animals)

Lab. exp.: Controlled observation and massive manipulation.

Front 15

What are the main objectives of scientific experiments?

Back 15

1. Test theoretical hypothesis

2. Discover and investigate new phenomena that cannot be explained by current theories

3. Illuminate or support policy making

Front 16

What is the advantage of testing hypothesis with experimental observation?

Back 16

Experimental observation allows for greater control of the auxiliary conditions.

Front 17

What is an experimental artifact?

Back 17

An interpretation of an experiment that is a mere illusion, unconnected to the real causes and phenomena.

Front 18

What is involved in experimental control?

Back 18

Accuratly identify the features of interest.

Influence these features in such a way that additional explanations can be ruled out.

Front 19

Name some means of controlling experiments!

Back 19

Blinding

Randomization

Effect separation

Preliminary experiments with extreme values

Front 20

What is the difference between repeating and replicating an experiment?

Back 20

Repeate: reproduce the experiment with all known details.

Replicate: reproduce the results of the experiment with a different setup. Checks how relieable the results are with different background conditions.

Front 21

What is the problem of external validity?

Back 21

1. Practical feasabilty

2. Ethical issues

3. Internal/external validity trade-off

Front 22

What is a double-blind experiment?

Back 22

An experiment where both the target and the one doing the treatment are blinded. E.g. in a medical study if the patient and the doctor do not know if the patient gets placebo or not.