Focus Group Data

The group consisted of the Researcher and four female participants from the PGCE Science Group at Reading University, October 2009. It met in the Autumn half term. The session took about 40 minutes and was concerned with the question: why do scientists measure?

The Researcher shared with the group outline details from a questionnaire held the previous week, in which the question had been part of the survey. Approximately 70% of the PGCE group of 42 responded that scientists measure because they wish to quantify or compare. The session was unstructured with the Researcher taking notes of the comments. The Researcher made very little input since the conversation flowed freely and along the lines of the question. The students all had higher degrees in sciences.

Students are identified by number:

R Why do scientists measure?
2. They do it to compare. Collaboration - using the same measuring system
4. To categorise and put into groups
1. To establish patterns and correlations
1. Important discoveries have been made this way, e.g the relation between lung cancer and smoking by statistics
4. Classification in biology, e.g. size of parasites used for identification
3. Used for identification by classification
2. Measuring and comparing numbers
3. Presence or absence - optimal
2. Allows other people to replicate investigations
1. E.g. epidemiological studies
2. Many scientific papers give insufficient methodological details and then they are not able to be repeated
3. For example, the autism study
1. Need at least 100 to be reasonable
3. Does cost play a part?
1. For university prestige
3. For example, between electron microscope vs optical microscope. one will measure more accurately, and your place might not have the best
2. Could go to another institution to use their equipment
4. Could use the equipment elsewhere, e.g. abroad
1. What did scientists do before they measured?
1. Everyday measurements were used e.g. inches
3. E.g milk in pints
2. Children's learning has a big effect on sue of everyday units, e.g. pints
4. I found it difficult dealing with feet because these were not in my background
2. Weight and pounds is difficult for me
4. I was brought up with metric
2. What about quarter pounders? Do they have them in France?
1. What about in Pakistan?
3. I have not been there long enough.
4. They foloow the British system
3. They measure distance in km
2. Distance and speed is an interesting one. When the teacher asked, the pupils referred to cars and mph but later they had to talk in metric
4. Everyday life is important
1. Statistics -crime is more in the US but should express it as a % of the population because US has such a lerge population
3. What is the smallest measurement made?
2. Angstroms
3. Are they measurable? By using a microscope?
2. By using X ray crystallography - how big is an Angstrom? 10 to the minus 26 or something?
All: refers to metric and going smaller
3. What about measuring the large such as going past km?
R. How far away are stars? how do they know?
All: many disjointed ideas were put forward together
4. Did Galileo do this
1. No. Galileo did gravity.
R. Can we measure something that does not exist e.g. distance to stars that have blown up?
4. Saturn has new rings.
End of recorded discussion


The data provides evidence for the following purposes of measurement in science (taken from the paper on the Measurement page in this wiki):
1. to support faithful replication of work by others;
2. to enable a detailed analysis of data, often based on statistical methods or in testing theoretical ideas.

The recorded discussion does not provide evidence for other purposes such as:
3. to characterise and elaborate a concept;
4. to provide for further predictions, known as fertility;
5. to examine the smoothness of data, that is, whether there are some otherwise hidden surprises in the collected data;
6. to promote the development of instruments for exploration.

The data focuses mainly on the following feature of the data:
2. reliability, or is the measurement repeatable?

The recorded discussion does not provide evidence for these features of the data:
1. Validity, or does the measurement measure what it claims to do?
3. Precision, or is the error in measurement so small that the value is very close to the actual value?
4. Accuracy, or is the error in the measurement so biased that even an average is some way from the actual value?

From this one recorded discussion, we can see that the written response to the question in the questionnaire fails to uncover some significant meanings, especially of comparability.