The objective of the Introduction is to provide evidence that justifies the hypotheses.
Each section of the Introduction builds on previous understanding. The first section of the Introduction builds a common understanding with the readers: a reasonable argument that the research is important. The second section of the Introduction builds positive arguments on the foundation of the shared understanding of importance. By identifying an unknown aspect of the important topic, the second section identifies a "gap" in understanding. The third section of the Introduction uses the gap in understanding to make a specific proposal to make a clear discovery about the important topic.
The third section of the Introduction involves three steps:
1) Clearly stating the overall goal or objective of the study. 2) Explaining how testing the General Hypotheses achieves the identified goal. 3) Explaining how the General Hypotheses lead to specific predictions (Measurable Hypotheses).
1) Clearly stating the overall goal or objective of the study.
The third section of an Introduction typically begins by stating the overall goal or objective for the proposed research. The research objective is the "deliverable" of the research project: the specific, important finding that readers can expect to take from the paper.
Research objectives can be written in different ways. One way to write a research objective is declaratively. For example, "Our objective is to determine the movement strategies used to maintain dynamic balance during walking in the elderly." The deliverable is a set of movement strategies used by the elderly.
In some contexts, research objectives can be posed as a question. For example, "Our research seeks to address the question: do elderly individuals use the same strategies to maintain dynamic balance as young individuals do?" The deliverable is the answer (yes or no) to the question of whether young and elderly use the same movement strategies.
Statements of research goals/objectives are typically one sentence long. However posed, clear and specific research goals are important touchstones for readers to understand the motivation for the study.
2) Explaining how testing the General Hypotheses achieves the identified goal.
Once a goal/objective of the study has been identified, a reasonable next step is to explain how testing the General Hypothesesachieve the goal.
An explanation is typically more than simply stating the General Hypotheses. Instead, the General Hypotheses are the conclusions of reasoned arguments with the goal of the study as the first premise. For example:
PREMISE 1: Our objective is to determine the movement strategies used to maintain dynamic balance during walking in the elderly.
PREMISE 2: Movement strategies for dynamic balance affect range of motion, movement variability, and responses to perturbations (The second section of the Introduction, identifying the gap in understanding, defends Premise 2).
CONCLUSION: Therefore, we hypothesize that elderly individuals will have significantly lower range of movement, higher movement variability, and less effective responses to perturbations than young individuals.
The goal of the study (e.g. Premise 1), conclusions from previous research (e.g. Premise 2), and other constraints (e.g. existing General Hypotheses, relevant study populations, experimental capabilities and limitations, etc.) can be premises for an argument that testing the proposed General Hypotheses is the most reasonable approach to achieving the goal.
3) Explaining how the General Hypotheses lead to testable predictions (Measurable Hypotheses).
Once the Introduction has defended the General Hypotheses, the Introduction can conclude by explaining the specific Measurable Hypotheses that can be reasonably predicted from the General Hypothesis. Measurable Hypotheses do not typically require much explanation. Often, the Measurable Hypotheses for a study are the predictions from the General Hypothesis that can be tested using feasible and valid quantitative measurements. However, it remains important to explain HOW each Measurable Hypothesis represents a prediction of the General Hypothesis.
For example, if our General Hypothesis is "we hypothesize that elderly individuals will have significantly lower range of movement, higher movement variability, and less effective responses to perturbations than young individuals," then we could create three Measurable Hypotheses:
MH1: Elderly individuals will have significantly lower range of hip, knee, and ankle flexion-extension movement during moderate speed walking than young individuals.
MH2: Elderly individuals will have significantly higher movement variability of hip, knee and ankle angles during moderate speed walking than young individuals.
MH3: Elderly individuals will take significantly more time to recover from lateral waist-pulls during moderate speed walking than young individuals.
Some authors include a brief paragraph summarizing the Methods after the hypotheses (at the end of the Introduction). However, if Measurable Hypotheses are sufficiently specific, then a summary of methodology should not be necessary.
Relatively short reasoned arguments should be sufficient to explain and justify how the General Hypothesis naturally follows from the overall objective of the study. Measurable Hypotheses should be clearly identifiable as specific predictions of the General Hypothesis.