Understanding Hypotheses and
Predictions
The terms hypothesis and prediction are sometimes used interchangeably,
but it’s important to understand the difference and include them as distinct
statements in the lab report.
Research Question
Before we get to the hypothesis, we must start at the beginning of the
research process, known as the scientific method, with a research question.
Research questions often stem from observations – these observations can
be made in passing, or they might come as a result of previous research. For
example, while out bird watching, you notice that a certain species of
sparrow made all of its nests with the same material: grasses. From that
observation, you might wonder, “Why are the nests of sparrows made with
grasses rather than twigs?” This is your research question.
Hypothesis
A hypothesis is, in simple terms, the answer to your research question. From
your question about sparrow nests, you would derive a hypothesis based on
your background research. You might hypothesize, “Sparrows use grasses in
their nests rather than twigs because grasses are the more abundant
material in their habitat.”
Prediction
A prediction, on the other hand, is specific to the study and experiment that
you design to test your hypothesis. It’s the outcome you would observe if
your hypothesis were supported. Predictions are often written in the form of
“if, then” statements, as in, “if my hypothesis is true, then this is what I will
observe.” Following our example, you could design an experiment wherein
birds are provided with differing quantities of the two nest materials, and
you could predict that, “If sparrows use grasses in their nests rather than
twigs because grasses are the more abundant material in their habitat, then
when twigs are more abundant, sparrows will use those in their nests.”
A more refined prediction might alter the wording so as not to repeat the
hypothesis verbatim: “If sparrows choose nesting materials based on their
abundances, then when twigs are more abundant, sparrows will use those in
their nests.”
Example
Let’s take a look at another example:
Hypothesis: When planted alongside asparagus, marigolds will deter
asparagus beetles.
Prediction: If marigolds deter asparagus beetles, then asparagus plants
planted alongside marigolds will host fewer asparagus beetles than
asparagus plants planted on their own.
A final note
Resist the urge to change your hypotheses and predictions based on the
outcome of your study or experiment. Your work will not be negated (or
marked down) because you didn’t find what you had expected. To the
contrary, an unexpected result often provides more area for discussion –
consider what about your background research led you to your hypotheses
and predictions and discuss why your research had an unpredicted outcome.
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