76 6 Background Chapters
Establishing Context
Tony was writing a thesis on the usefulness of laser grading of irrigated farmland.
In this process, laser-guided machinery is used to grade the land to high precision,
so that the irrigation water will flow evenly, the depth of flooding required to ensure
that the whole area is properly irrigated is reduced, and no areas are left water-
logged. These good effects may be counterbalanced by alterations to plant growth
caused by disturbance to the soil by the grading operation, for example, through loss
of soil nutrients and bacteria. To understand all of these effects, the reader needs a
description of the interaction between soil, water, plants, and air.
How much of this should Tony have included as a background chapter? At first
he left it all out, assuming the reader would know as much about this as he did. I,
his supervisor, didn’t, and told him that he would have to include enough of this
material so that the policy-maker, as distinct from the agricultural scientist, would
be able to understand what he was talking about. A week or so later I asked how his
description of the soil and plants was going, and he told me that he had written about
30 pages and was only halfway through. He was busily paraphrasing from half a
dozen standard soil texts and distilling the thoughts of the three soil scientists he had
previously interviewed. What he should have been doing was something between
these two extremes.
How can you determine what to omit, and what to include, as you establish con-
text? I suggest three rules:
- Don’t include material that the reader does not need in order to understand what
will follow. Although we need some chemistry to understand the effects of bicar-
bonate soda in baking, there is a lot that is not relevant to the problem. - Don’t include anything in your main text if it is going to interrupt the develop-
ment of the flow of logic in your argument. There may be some things that have
to be included in the thesis, but that should be in appendices rather than the main
text. - Include anything that is genuinely clarifying.
The 95 % Syndrome
As students get further and deeper into their projects, they often fail to realize how
expert they have become in their area. They have absorbed the key ideas that domi-
nate their particular field and have come to take them for granted. When they start
writing about their own research, which is about the extension and modification of
these ideas, they assume that the reader will be just as familiar with the basic ideas
as they are, and they don’t bother to explain them properly. They assume the 95 per
cent and concentrate on the 5 per cent.