Research Hypothesis: Definition, Elements, Format, Types of Research

Research Hypothesis DefinitionWhen a proposition is formulated for empirical testing, we call it a hypothesis. Almost all studies begin with one or more hypotheses. A hypothesis, more specifically, a research hypothesis, is formulated to predict an assumed relationship between two or more variables of interest.

If we reasonably guess that a relationship exists between the variables of interest, we first state it as a hypothesis and then test it in the field.

Hypotheses are stated in terms of the particular dependent and independent variables that are going to be used in the study.

Research Hypothesis Definition

A research hypothesis is a conjectural statement, a logical supposition, a reasonable guess, and an educated prediction about the nature of the relationship between two or more variables that we expect to happen in our study.

Unless you are creating an exploratory study, your hypothesis should always explain what you expect to happen during your experiment or research.

Remember, a hypothesis does not have to be correct. While the hypothesis predicts what the researchers expect to see, the goal of the research is to determine whether this guess is right or wrong. When experimenting, researchers might explore some different factors to determine which ones might contribute to the outcome.

In many cases, researchers may find that the results of an experiment do not support the original hypothesis. When writing up these results, the researchers might suggest other options that should be explored in future studies.

Elements of a Good Hypothesis

Regardless of the type of hypothesis, the goal of a good hypothesis is to help explain the focus and direction of the experiment or research. As such a good hypothesis will

  • State the purpose of the research.
  • Identify which variables are to be used.

A good hypothesis;

  • Needs to be logical.
  • Must be precise in language.
  • Should be testable with research or experimentation.

A hypothesis is usually written in a form where it proposes that if something is done, then something will occur.

Finally, when you are trying to come up with a good hypothesis for your research or experiments, ask yourself the following questions:

  • Is your hypothesis based on any previous research on a topic?
  • Can your hypothesis be tested?
  • Does your hypothesis include independent and dependent variables?

Before you come up with a specific hypothesis, spend some time doing background research on your topic. Once you have completed a literature review, start thinking of potential questions you still have. Pay attention to the discussion section in the journal articles you read. Many authors will suggest questions that still need to be explored.

Basic Format of a Good Hypothesis

A hypothesis often follows a basic format of “If {this happens}, then {this will happen}.” One way to structure your hypothesis is to describe what will happen to the dependent variable if you make changes to the independent variable.

The basic format might be:

“If {these changes are made to a certain independent variable}, then we will observe {a change in a specific dependent variable}.”

A few examples:

  • Students who eat breakfast will perform better on a math test than students who do not eat breakfast.
  • Students who experience test anxiety before an exam gets higher scores than students who do not experience test anxiety.
  • Drivers who talk on the mobile phone while driving will be more likely to make errors when on driving than those who do not talk on the phone.
  • People with high exposure to ultraviolet light will have a higher frequency of skin cancer than those who do not have such exposure.

Look at the last example.

Here the independent variable (exposure to ultraviolet light)) is specified, and the dependent variable (skin cancer) is also specified. Notice also that this research hypothesis specifies a direction in that it predicts that the people with exposure to ultraviolet light will have a higher risk of cancer.

This is not always the case. Research hypotheses can also specify a difference without saying which group will be better or higher than the other.

For example, one might formulate a hypothesis of the type: ‘Religion does not make any significant difference in the performance of cultural activities.’ In general, however, it is considered a better hypothesis if you can specify a direction.

Research hypotheses serve several important functions. The most important one is to direct and guide the research. A few of the other functions of the research hypothesis are enumerated below:

  • A research hypothesis indicates the major independent variables to be included in the study;
  • A research hypothesis suggests the type of data that must be collected and the type of analysis that must be conducted to measure the relationship;
  • A research hypothesis identifies facts that are relevant and that are not;
  • A research hypothesis suggests the type of research design to be employed.

Types of Research Hypothesis

Two types of research hypothesis are;

  1. Descriptive hypothesis.
  2. Relational hypothesis.

Descriptive Hypotheses

Descriptive hypotheses are propositions that typically state the existence, size, form, or distribution of some variables. These hypotheses are formulated in the form of statements in which we assign variables to cases.

For example,

  • The prevalence of contraceptive use among the currently married women in Bangladesh exceeds 60%.

In this example, the case is ‘currently married women,’ and the variable is ‘prevalence of contraceptives.’ As a second example,

  • The public universities in Bangladesh are currently experiencing budget difficulties.

Here’ public universities’ is the case, and ‘budget difficulties’ is the variable.


  • The National Board of Revenue claims that over 15% of potential taxpayers falsify in their income tax return.
  • At most, 75% of the pre-school children in community A have a protein-deficient diet.
  • The average sales in a superstore exceed taka 25 lac per month.
  • Smoking increases the risk of lung cancer.
  • The average longevity of women is higher among females than among males.
  • Gainfully employed women tend to have lower than average fertility.
  • Women with child loss experience will have higher fertility than those who do not have such experiences.

All examples of descriptive hypotheses.

It is important to note that the Descriptive hypothesis does not always have variables that can be designated as independent or dependent.

Relational Hypotheses

Relational hypotheses, on the other hand, are the statements that describe the relationship between variables concerning some cases. For example,

  • Communities with many modern facilities will have a higher rate of contraception than communities with few modern facilities.

In this instance, the case is ‘communities,’ and the variables are ‘rate of contraception’ and ‘modern facilities.’ Similarly, “People who use chewing tobacco have a higher risk of oral carcinoma than people who have never used chewing tobacco’ is a relational hypothesis.

A relational hypothesis is again of two types: correlational hypothesis and the causal hypothesis. A correlational hypothesis merely states that variables occur together in some predictable relationships without implying that one variable causes the other to change or take on different values. Here is an example of a co-relational hypothesis:

  • Males are more efficient than their female counterparts in typing.

In making such a statement, we do not claim that sex (male-female) as a variable has any influence on the other variable’ typing efficiency’ (less efficient-more efficient). Here is one more example of a correlational hypothesis:

  • Saving habit is more pronounced among Christians than the people of other religions.

Once again, religion is not believed to be a factor in saving habits, although a positive relationship has been observed.

Look at the following example:

  • The participation of women in household decision making increases with age, their level of education, and the number of surviving children.

Here too, women’s education, several surviving children, or education does not guaranty their autonomy in decision making.

With causal hypotheses (also called explanatory hypotheses), on the other hand, there is an implication that a change in one variable causes a change or leads to an effect on the other variable.

A causal variable is typically called an independent variable, and the other the dependent variable. It is important to note that the term “cause’ means roughly to mean ‘help make happen.’ So, the independent variable need not be the sole reason for the existence of or change in the dependent variable. Here are some examples of causal hypotheses:

  • An increase in family income leads to an increase in the income saved.
  • Exposure of mothers to mass media increases their knowledge of malnutrition among their children.
  • An offer of a discount in a department store enhances the sales volume.
  • Chewing tobacco increases the risk of oral carcinoma.
  • Goat farming contributes to poverty alleviation of rural people.
  • The utilization of child welfare clinics is the lowest in those clinics in which the clinic personnel are poorly motivated to provide preventive services.
  • An increase in bank interest rate encourages the customers for increased savings.

In the above example, we have ample reasons to believe that one variable (for example, family income and savings, misuse of credit, and farm size) has a bearing on the other variable.

We cite two more examples to illustrate the hypothesis, general objective, ultimate objective, and a few specific objectives.

General objective:

  • To compare the complications of acceptors of laparoscopic sterilization and mini-laparotomy among Bangladeshi women.

Research hypothesis:

  • The risk of complications is higher in the mini-laparotomy method of sterilization than laparoscopic sterilization.

Specific objectives:

  • To assess the complications of laparoscopic sterilization and mini-laparotomy.
  • To assess service providers’ knowledge and perception regarding the complications, preferences, and convenience of the two methods.

Ultimate Objectives:

  • To introduce and popularize laparoscopic female sterilization method in the National Family Planning Program to reduce rapid population growth rate.

In a study designed to examine the living and working conditions of the overseas migrant workers from Bangladesh and the pattern of remittances from overseas migrant workers, the general objective, specific objectives, and the ultimate objective were formulated as follows:

General objective:

  • To examine the living and working conditions of the overseas migrant workers from Bangladesh.”

Specific objectives:

  • Characteristics of migrant workers by significant migration channels;
  • Countries of destination;
  • The occupational skill of the workers;
  • Pattern and procedures of remittances;
  • Impact of remittances on government revenue;
  • Better utilization of remittances.

Ultimate objective:

  • To suggest ways and means minimize the differences in the policy adopted by the public and private sectors in their recruitment process in the interest of the workers;
  • To ascertain the extent of possible exploitation of the workers by the private agencies and suggest remedies for such exploitation.

Research hypothesis:

  • Private agencies, in most cases, exploit migrant workers.

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