Sensitivity and Specificity

Jane Austen's Lost Statistical Masterpiece

An entertainment by Martin Bland


In the original 1996 production, the author played the narator and Mr. Darcy, the part he was born for as surely as Arnold Schwarzenegger was born to play Conan the Barbarian. Curiously, this got a big laugh from his wife! The part of Miss Bennet was taken by Dr. Janet Peacock, Bingley by Mr Iain Carey, Wickham by Dr. Jan Poloniecki, and Miss Austen's own voice was provided by Mrs. Jennifer Taylor.


Narrator:

The following is a fragment found inside a book in a hotel in Bakewell, Derbyshire, where Jane Austen is known to have written "Persuasion" (according to the management). The manuscript is difficult to read in places, and the whole is crossed through diagonally, suggesting that the author decided to abandon the whole enterprise, possibly in favour of a screenplay for Miss Emma Thompson. We thought that, incomplete though it is, it should be presented to the world. We have chosen to do this in dramatic form, as that is how Miss Austen's works are now usually received.

Here, then, is Jane Austen's lost statistical masterpiece: "Sensitivity and Specificity".

Jane Austen:

It is a truth universally acknowledged, that an ambitious doctor in possession of a diagnostic test, must be in want of a national screening programme.

Dr. Elizabeth Bennet was no exception. She had discovered that trifling of the affections could be predicted reliably by the presence of the smouldering look. In search of a grant of five thousand a year, Dr Bennet approached the Regional R&D director, Professor Darcy.

Doctor Bennet:

Sir, trifling with the affections is a serious condition and very costly to the NHS. My data show that 98% of cases of trifling, as defined by the gold standard of secret engagement elsewhere, first presented with smouldering. Five thousand a year would fund research to rid England of this curse.

Professor Darcy:

To get five thousand a year, ma'am, you need a proposal. I hear that Mr. Bingley, the statistician, is an excellent adviser in cases of this sort.

Jane Austen:

Mr. Bingley was approached, and invited Doctor Bennet, properly chaperoned by a B.Sc. student, to visit him in his office.

Doctor Bennet:

Well, Mr. Bingley, I have found that the smouldering look sign is almost always found in cases of trifling of the affections.

Mr. Bingley:

But, Doctor Bennet, is trifling of the affections a serious condition, worthy of the taxpayer's five thousand a year?

Doctor Bennet:

Of course, sir. In many cases of trifling, young women have been known to experience the vapours, which may lead to a decline, followed by a fever in which the life of the unhappy young woman is despaired of.

Mr. Bingley:

With so sensitive an indication as yours, Doctor Bennet, I think that not five but ten thousand a year is warranted. For that we can get three statisticians straight off M.Sc. courses to analyse these data, and have enough beside to attend the International Conference of Water Takers at the University of Bath.

May I offer to be a collaborator, ma'am, and calculate the power and sample size?

Jane Austen:

Had Doctor Bennet imagined it, or had Mr. Bingley cast a smouldering look in her direction? Was it her he cared for, or was he merely looking for a trifling addition to his CV?

The next day, Doctor Bennet wrote a long letter to Professor Darcy, explaining the desirability of a national screening programme to detect early trifling, the need for a randomized trial of the smouldering look sign, the power of the study, and the requirement for ten thousand a year.

Doctor Bennet:

I'm not quite sure what Mr. Bingley meant by "power", but I know that Professor Darcy will expect it. But if I change all the numbers I can raise the funds required to fifteen thousand a year. I can then include a Grand Tour of international conferences. Now I shall post this to Professor Darcy. As he is in central London, I must pray that it actually gets there.

Jane Austen:

Professor Darcy was much taken with this missive, yet felt obliged to seek a further statistical opinion. He sought out that of Professor "Two Brains" Wickham, who replied at length, in the greatest of confidence. Naturally, Professor Darcy passed this letter to Doctor Bennet.

When the letter arrived, Doctor Bennet retreated to her chamber, where she stayed for three days, refusing all food. Was the proposal to be rejected, and the fifteen thousand a year lost? She resolved to face Professor Wickham boldly.

Doctor Bennet:

Why, sir, have you spoken so ill of my request for a mere fifteen thousand a year? I have shown smouldering look to be highly sensitive, and to be found in almost all cases of trifling with affections.

Professor Wickham:

But Doctor Bennet, you forget the specificity of the sign. Is it not the case that there are women whose affections have not been trifled, yet where smouldering has been observed? What proportion of those safely married have experienced smouldering? And what of the positive predictive value? This depends on the prevalence of trifling, linked by a simple equation found in many good statistics textbooks, such as my own.

Doctor Bennet:

As to that, Professor Wickham, I fear that trifling is all too common, and that without it these stories would lose what little interest they have.

Narrator:

At this point another hand has added: "Needs more nipples, let's do Moll Flanders instead" and the manuscript ends.


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Last updated: March 18, 2015.