Scientific Method and Mixed Methods in Human Services Research

The Four Steps of the Scientific Method

The scientific method is a systematic approach to testing hypotheses in research. Its four steps are as follows:

Step 1: "Observation and description of a phenomenon or group of phenomena" (Introduction to the scientific method, 2012). The scientific method begins with existing research and builds upon the work of other individuals in the field and/or observation of a particular phenomenon.

Step 2: "Formulation of a hypothesis to explain the phenomena" (Introduction to the scientific method, 2012). The hypothesis is what is tested over the course of the experiment. It must be specific — not merely descriptive — and sufficiently limited so that other variables that could cause the phenomenon can be eliminated.

Step 3: "Use of the hypothesis to predict the existence of other phenomena, or to predict quantitatively the results of new observations" (Introduction to the scientific method, 2012).

Step 4: "Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments" (Introduction to the scientific method, 2012). A hypothesis is not confirmed by a single experiment alone, given that experiments can be affected by unaccounted-for variables, random chance events (especially in small samples), and observer bias. After drawing conclusions from an initial experiment, the researcher must retest the results and, if necessary, further isolate the conditions under scrutiny.

Challenges of Applying the Scientific Method to Human Research

When conducting research on human beings, it can be more difficult to formulate hypotheses that eliminate other influencing phenomena or to create a perfectly representative control group that mirrors the experimental group in all respects except the variable under study. When studying human beings, researchers are limited — both ethically and logistically — in how much they can control variables, compared with studying the laws of nature.

A Proposed Obesity Intervention Study

One example of the scientific method applied in human services might address the question of whether a program emphasizing diet or exercise is more effective in promoting weight loss among low-income African-American teenage girls. A study could hypothesize that dietary intervention is more effective, based on research suggesting that there is a limit to how much exercise can compensate for a poor diet — particularly given teens' increasingly sedentary lifestyles when they are not actively exercising.

One relevant study found that "while engaging in high levels of physical activity is a good bet for preventing obesity in white adolescent girls, it does not give their black peers the same benefit. The study, published in the Archives of Pediatrics and Adolescent Medicine, found that among black adolescent girls who moved the most at age 12, obesity at age 14 was nearly as likely as it was for those whose activity rates were far lower" — a finding attributed to the excessively caloric diets of the girls (Healey, 2012). As Healey (2012) notes, "In African-American households headed by a single parent struggling to feed kids on a limited income…if you have to eat off the dollar menu, that's what you do," and family cooking traditions that emphasize less healthful foods and preparation methods can be difficult to change.

In a proposed study based on this existing research, four groups of African-American teenage girls with a similar range of BMI would be created. One group would receive an intervention based primarily on dietary reform; a second group would focus on exercise. A third group would participate in a combined dietary and exercise modification program, and a fourth group would serve as the control. Each girl's BMI would be assessed before and after the program and again one year following the intervention.

It would be hypothesized that the greatest reduction in BMI would occur in the dietary intervention group and the combined dietary-and-exercise intervention group. If weight loss were greatest in the diet-only group, or equal between the first and third groups, this would support the primacy of dietary modification over exercise as a weight-loss strategy. However, given the many variables that can affect individual body weight, it would be essential to retest this hypothesis multiple times among different populations of low-income African-American girls.

Conclusion: Why Sound Research Matters in Human Services

The ambiguity of the causes of human phenomena is why sound research is so vitally important in the field of human services. Unlike the natural world, the sources of human behavior are often ambiguous. Additionally, researchers may interpret human behavior differently than human subjects themselves would. This is precisely why the use of both qualitative and quantitative data can be so beneficial in developing human services programs that address the genuine needs of the target population and make effective use of scarce financial resources.

References

Healey, M. (2012). Exercise benefits black girls less than whites. Los Angeles Times.

Introduction to the scientific method. (2012). [University].

The qualitative vs. quantitative debate. (2012). [University].