An Apple A Day...

Research has once again shown the benefit of eating fruit or vegetable.  Yesterday the news media was full of headlines like this:

“Fabulous” I thought.  “I wonder where this research came from?”   

So I decided to follow the research back to its origins - a fairly straightforward task.  It turns out that the research was published in the British Medical Journal’s Christmas edition – a traditionally light-hearted edition often with slightly less-than-serious research articles.

For example, here is a selection of the titles of other articles in the Christmas 2013 edition:

The good news is that many of the articles are open access so you could download them and use them with students to show what a research paper looks like and how they are structured.  The light-hearted topics means that they are more ‘accessible’ than traditional research papers, but are still structured in the same way.  It could also be used to look at how computer modelling is used to look at the potential effectiveness of medical interventions without actually carrying out the intervention.

If you want to do that then the link to the apple story is here.

I heard/read a number of comments about the value of prescribing an apple instead of statins, such as this tweet:

I wondered about the cost-effectiveness of prescribing an apple a day to the population over 50 (around 21 million people according to this source).  Pleasingly, the authors of the paper actually calculate the cost of prescribing statins (to everyone over 50 who isn’t already taking them for other medical reasons) and the cost of prescribing apples.

Cost of additional Statins: £180 million

Cost of apples: £260 million

So, if the NHS were to prescribe apple, which I envisage to be a little like fruit time in primary school, it would cost more than £80 million MORE than prescribing statins.  

Of course, the statins have additional side effects which would have to be taken into account.  The authors also assumed that calorie intake would remain the same if everyone ate an apple, but that might not be the case, so the side effects from that should also be considered.

Interesting questions to ask:

• Why might people be happy to pay for an ‘apple a day’, but not a ‘statin’ a day?
• Could/Should the NHS prescribe fruit&vegetables in the same way that they prescribe medications?
• The authors assume a 70% compliance rate in eating the apple – is this realistic?
•   Should researchers spend time writing light-hearted research articles?
• Why did the news media pick up on the story, and report it without comment on the reasons why it was written?

 Enjoy, and do let me know if you use this in class.

 

How many students get G?

Will there be lots of students who are 'demotivated' by the new grading structure for the GCSEs?

On 16th November the BBC published a story about the new grading structure that will be brought in for the revamped GCSEs in (initially) English and Maths in 2015 and then in the other Ebacc subjects in 2016.

The new structure will see the loss of letter grades (A* to G) and in their place will be numerical grades (9 to 1), with 9 being at the top of the scale and 1 at the bottom.  In their response to the GCSE consultation Ofqual said:

"In response to feedback to our consultation, we have moved from the eight grades we proposed to nine grades. In part this was to avoid the risk of people assuming that eight new grades would map onto the current eight grades. We also want to avoid the risk of reducing the opportunity for less able students to demonstrate the progress they have made and have their achievements recognised." pg 6

So Ofqual were not giving many details about the equivalence of 'old' and 'new' gradings.  However, the BBC report suggests the following potential equivalence:

"Ms Marshall, from King's College London, has told the BBC she understands that for English at least, there will only be one or two grades below the equivalent of a C.
"It's my understanding that there will be more or less three levels for A grades, two levels for a B and two for a C," she said."

Which of course, leaves two levels for grades lower than a (current) C, rather than the current four.

I wondered how many students this would affect?

Each year, once the examining season is done and dusted, and results day has arrived JCQ publishes details of the results for that session.

The following are the percentage of students in English and Maths that achieved each grade.

English (731153 students sat the exam):
A* 3.3%   A 10.9%   B 20.3%   C 29.1%   D 21.5%   E 9.2%  F 3.8%   G 1.2%  U  0.7%
(36.4% of students achieving D - U)

Maths (760170 students sat the exam):
A* 4.9%   A 9.4%   B 16.2%   C 27.1%   D 18.1%   E 10.0%  F 6.9%   G 4.7%  U  2.7%
(35.5% of students achieving D - U)

From these figures, we can see that there are far fewer students at the bottom end of the scale than at the top end.  The grading system currently provides very finely differentiated marks for E - U grades, and much less differentiation at A* - C).

I can therefore see the strong justification for providing a much smaller grade range below the nominal 'good' grade.

Of course, this doesn't address the fact that the 'new' GCSEs are likely to be harder than the old ones, so perhaps students getting a C currently, wouldn't do so in the future.

.....................................................................................................................................................
Out of interest, the figures for the various sciences are:

Biology (174428 students sat the exam)
A* 14.4%   A 26%   B 28.3%   C 21.1%   D 7.7%   E 1.7%  F 0.5%   G 0.3%  U  0.1%
(10.3% of students achieving D - U)

Chemistry (166091 students sat the exam)
A* 16.6%   A 25.6%   B 26.9%   C 20.9%   D 7.7%   E 1.7%  F 0.4%   G 0.1%  U  0.1%
(10% of students achieving D - U) 

Physics  (160735 students sat the exam)
A* 16.0%   A 25.5%   B 27.8%   C 21.5%   D 7.4%   E 1.3%  F 0.3%   G 0.1%  U  0.1%
(9.2% of students achieving D - U) 

Science (451433 students sat the exam)
A* 1.4%   A 6.7%   B 16.2%   C 28.8%   D 24.6%   E 12.5%  F 6.0%   G 2.5%  U  1.3%
(46.9% of students achieving D - U)

Additional Science (283391 students sat the exam)
A* 2.6%   A 9.2%   B 20.0%   C 32.3%   D 20.6%   E 8.9%  F 4.0%   G 1.6%  U  0.8%
(35.9% of students achieving D - U)