Oxford Medicine Interview: A Graph Question

Louis M. · Medicine (Oriel College, Oxford)

Hi, I'm Louis, a third-year medical student at Oriel College, Oxford. I want to give you an example of the type of question you can expect at an Oxbridge medical interview, using a graph I was actually handed in mine. Graph questions come up a lot in medicine interviews, because they test whether you can read data accurately, interpret a trend, and then reason about what might lie behind it. I'll walk you through the questions I was asked and how I approached each one.

The graph they handed me

The graph showed the number of deaths from tuberculosis per million of the population per year, roughly between 1830 and 1960. It's a long, steep decline, and that shape is the whole story, so the first job is simply to read it properly before trying to explain anything.

Question one: what does this graph show?

The opening question was just that: what does this graph show? Even if you can't identify the disease from clues on the chart, such as the point where the tubercle bacillus was identified or where BCG vaccination was introduced, you can still describe the data with confidence. The graph shows a reduction in the death rate over time, from around 4,000 per million per year down to only about 50 per million per year. Always describe before you interpret. A clear statement of the trend is already a strong answer, and it buys you a few seconds to gather your thoughts.

Question two: what is chemotherapy?

Next I was asked what I understood by the term chemotherapy. Most people immediately associate it with cancer, but chemotherapy really means the chemical treatment of any disease. In this case the disease is tuberculosis, caused by the bacterium Mycobacterium tuberculosis, and the chemotherapy is an antibiotic drug. Taking a familiar word and giving its precise, broader meaning is exactly the kind of small, clear thing that lands well in an interview.

Question three: the trick question

Then came the real one: what do you think was the most important contribution to the fall in tuberculosis deaths in the period shown? This is something of a trick question, designed to get you thinking about the causes and treatments of disease.

Look closely and you'll notice that none of the three medical advances marked on the graph has much effect on the absolute number of deaths per year. The death rate was already falling steeply before they appeared. Because the question is deliberately broad, the interviewers are inviting you to move beyond the scope of the graph and suggest other factors that contributed to the decline.

Two stand out. Sanitation improved drastically within this time frame, which would have contributed in large part to reducing the spread of tuberculosis, and therefore the deaths from it. Nutrition is another key example: better nutrition improves the immune system's ability to protect against the infection and against the progression of diseases such as tuberculosis. Recognising that public health measures, not just the medical interventions on the chart, drove most of the fall is a sign of genuine clinical and scientific thinking.

What the interviewers are really testing

The point of the question isn't to know a fact about tuberculosis. It's to see whether you'll accept the obvious answer, the medical advances, or actually check that answer against the data and notice it doesn't hold up. A few habits earn credit here:

• describing the data clearly before interpreting it
• defining your terms precisely, even everyday ones
• treating a broad question as permission to widen the discussion
• being willing to look past the labels on a graph to social and environmental factors

Common mistakes to avoid

The usual slips are easy to picture. Jumping straight to interpretation without saying what the axes and trend actually show. Reaching for the "expected" answer, the marked medical advances, even though the data doesn't support them as the main cause. Using a term like chemotherapy loosely instead of defining it. And stopping at the first plausible factor when the question is clearly asking you to think more widely.

Final thoughts

Describe the data before you explain it, define even the familiar terms carefully, and when a question is deliberately open, take that as an invitation to bring in wider factors like sanitation and nutrition rather than digging further into the graph. Above all, don't just give the answer the chart seems to want. If you'd like to know more about applying to Oxbridge or preparing for interviews, Oxbridge Solution is happy to help.