Analysis of marks

After a couple of months there have been 18 responses but 3 of these were blank so only 15 sets of marks. This is not enough to base any statistical analysis on (although we ask our students to do this all the time in their practical work) but might be worth a comment or two.

The range of marks was from 16 to 22

16 2 13.3%
17 3 20%
18 1 6.7%
19 2 13.3%
20 2 13.3%
21 4 26.7%
22 1 6.7%

This seems like a big difference but if you think in % then its from 67% to 92% so everyone agreed that this is a good report in the 6-7 region (assuming 70% is approximately 7)

I have compiled the individual grades to see if there is a pattern.

  • First this to notice is that a couple of teachers added up the scores incorrectly so the minimum was 15 not 16.
  • The low markers were consistently low in all criteria.
  • With 5 criteria, two teachers can agree with most of the statement but disagree on the 1/2, 3/4 and 5/6 boundaries resulting in a difference of 5 marks, even thought they pretty much agree.

Let's look at the breakdown for each criteria.
To make things simpler I have written down the scores for individual criteria as 0123 rather that 0, 1/2, 3/4 and 5/6. This is a bit of a problem since within each statement there are 2 possible grades.

Personal Engagement

Here there is a big difference in opinion.

I think the reason for this is that some markers marked this down because the student didn't specifically say that he was interested in radioactivity. I don't think this matters, the student was clearly engaged in finding out the answer to his research question, he was creative in his use of apparatus, this is not a standard experiment.


Again quite a spread of grades.

  • It certainly is a focused piece of research so not sure why some markers scored so low in the first column.
  • There wasn't a great deal of background theory hence the low marks in column 2.
  • Column 3 is the appropriateness of the method. I think this was god use of the apparatus. Everyone agrees with this.
  • Apart from one marker everyone agreed that he had taken into consideration the uncertainties.
  • To say that there was no consideration of safety issues is clearly not true. The marker must have missed the statement on this. Low scores in this category seems to have brought the score down in several cases.


All reasonably high scores. The student used all the tricks plotting both a curve and a straight line.

The student didn't expect an exponential relationship so the experiment served its purpose in revealing this. It depends on the type of source but I think this fits with expectations of the absorption of radiation by matter.


Some markers seemed to disagree with the conclusion that this was an exponential relationship even though the data clearly supports this conclusion. Maybe they were expecting an inverse square relationship? This might have been the case but he kept the distance between source and detector constant.

The conclusion and evaluation could certainly have been more detailed but to say the standard had not been reached at all is not true.


Not a big spread here, everyone agrees this is well written.

  • Interesting to note the 2nd and 3rd entry. 2nd scores 2221 to give 3 and the 3rd 1221 to score 4!
  • Also the 3rd to last. 2222 scoring 3.
  • These discrepancies are probably due to the split scores that don't appear in my summary, although it does seem that the harsh markers apply the best fit more conservatively.

So, there was a wide range but the big question is "would the moderator mark the high scores down or the low scores up"?

Probably neither. What we don't have here is the actually marked script with comments and justifications. When the moderator sees the full picture he/she will be much more likely to support the teacher.

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