HOW TO WRITE A HYPOTHESIS: A STEP-BY-STEP GUIDE
- Ask a Question
The starting point for any hypothesis is asking a question. This is often called the research question. The research question is the student’s jumping-off point to developing their hypothesis. This question should be specific and answerable. The hypothesis will be the point where the research question is transformed into a declarative statement.
Ideally, the questions the students develop should be relational, i.e., they should look at how two or more variables relate to each other as described above. For example, what effect does sunlight have on the growth rate of lettuce?
- Research the Question
The research is an essential part of the process of developing a hypothesis. Students will need to examine the ideas and studies that are out there on the topic already. By examining the literature already out there on their topic, they can begin to refine their questions on the subject and begin to form predictions based on their studies.
Remember, a hypothesis can be defined as an ‘educated’ guess. This is the part of the process where the student educates themself on the subject before making their ‘guess.’
- Define Your Variables
By now, your students should be ready to form their preliminary hypotheses. To do this, they should first focus on defining their independent and dependent variables. Now may be an excellent opportunity to remind students that the independent variables are the only variables that they have complete control over, while dependent variables are what is tested or measured.
- Develop Your Preliminary Hypotheses
With variables defined, students can now work on a draft of their hypothesis. To do this, they can begin by examining their variables and the available data and then making a statement about the relationship between these variables. Students must brainstorm and reflect on what they expect to happen in their investigation before making a prediction upon which to base their hypothesis. It’s worth noting, too, that hypotheses are typically, though not exclusively, written in the present tense.
Students revisit the different types of hypotheses described earlier in this article. Students select three types of hypotheses and frame their preliminary hypotheses according to each criteria. Which works best? Which type is the least suitable for the student’s hypothesis writer?
- Finalize the Phrasing
By now, students will have made a decision on which type of hypothesis suits their needs best, and it will now be time to finalize the wording of their hypotheses. There are various ways that students can choose to frame their hypothesis, but below, we will examine the three most common ways.
The If/Then Phrasing
This is the most common type of hypothesis and perhaps the easiest to write for students. It follows a simple ‘If x, then y’ formula that makes a prediction that forms the basis of a subsequent investigation.
E.g.,
If I eat more calories, then I will gain weight.
Correlation Phrasing
Another way to phrase a hypothesis is to focus on the correlation between the variables. This typically takes the form of a statement that defines that relationship positively or negatively.
E.g.,
The more calories that are eaten beyond the daily recommended requirements, the greater the weight gain will be.
Comparison Phrasing
This form of phrasing is applicable when comparing two groups and focuses on the differences that the investigation is expected to reveal between those two groups.
E.g.,
Those who eat more calories will gain more weight than those who eat fewer calories.
Questions to ask during this process include:
- What tense is the hypothesis written in?
- Does the hypothesis contain both independent and dependent variables?
- Is the hypothesis framed using the if/then, correlation, or comparison framework (or other similar suitable structure)?
- Is the hypothesis worded clearly and concisely?
- Does the hypothesis make a prediction?
- Is the prediction specific?
- Is the hypothesis testable?
- Gather Data to Support/Disprove Your Hypothesis
If the purpose of a hypothesis is to provide a reason to pursue an investigation, then the student will need to gather related information together to fuel that investigation.
While, by definition, a hypothesis leans towards a specific outcome, the student shouldn’t worry if their investigations or experiments ultimately disprove their hypothesis. The hypothesis is the starting point; the destination is not preordained. This is the very essence of the scientific method. Students should trust the results of their investigation to speak for themselves. Either way, the outcome is valuable information.
