Reviewing the Literature

By conducting a review of the literature, re­searchers refine the problem under study, clarify possible techniques to be used in collecting data, and may avoid making unnecessary mistakes. When David Snow and his colleagues began con­sidering mental illness among the homeless, they turned to two types of literature. First, they re­viewed "popular" magazines such as Time, News-week, and People and found a consistent image of

CHAPTER TWO ♦ METHODS OF

SOCIOLOGICAL RESEARCH

the homeless as "street people" who had previ­ously spent time in mental hospitals. Second, they examined systematic studies done in Boston, New York, and Philadelphia which indicated that homeless persons coming to emergency shelters and psychiatric hospitals were usually found to have a diagnosable mental illness.

But were these studies representative of the homeless? Still further review showed that when researchers focused on the homeless in general— rather than solely on those treated by psychiatri-cally based agencies under emergency condi­tions—the proportions of homeless persons found to be mentally ill were much lower (Ohio Department of Mental Health, 1984; Roth et al., 1985; Snow et al., 1986:407-408). These conflict­ing findings called into question the common media image of the homeless as predominantly mentally ill. The researchers' review of the litera­ture underscored the importance of thoroughly examining previous studies that use different techniques before proceeding with one's own research.

Formulating the Hypothesis

After reviewing earlier research concerning the homeless and drawing upon the contributions of sociological theorists, the researcher may develop an intuitive guess about the relationship between mental illness and homelessness. Such a specula­tive statement about the relationship between two or more factors is called a hypothesis.

A hypothesis essentially tells us what we are looking for in our research. In order to be mean­ingful, a hypothesis must be testable; that is, it must be capable of being evaluated. The state­ment "God exists" may or may not be true; it clearly cannot be scientifically confirmed. A re­search hypothesis must also be reasonably spe­cific. "Young people have more fun" and "Florida is nicer than California" are statements that lack the kind of precision that sociologists need in order to collect suitable data.

As part of a study of homelessness, one possible hypothesis might be: "Most homeless persons are not mentally ill." In formulating a hypothesis, we do not imply that it is correct. We merely suggest that it is worthy of study, that the hypothesis

should be scientifically tested and confirmed, re­futed, or revised, depending on the outcome of the study (G. Bogue, 1981:11).

A hypothesis usually states how one aspect оf human behavior influences or affects another. These aspects or (actors are called variables. A variable is a measurable trait or characteristic that is subject to change under different conditions. Income, religion, occupation, and gender can all be variables in a study. In the hypothesis pre­sented above, there are two variables: "homeless­ness" and "mental illness."

In developing hypotheses, sociologists attempt to explain or account for the relationship be­tween two or more- variables. If one variable is hypothesized to cause or influence another one, social scientists call the first variable the indepen­dent variable. The second is termed the dependent variable because it is believed to be influenced by the independent variable. In their study of the homeless, researchers were interested in the ef­fect that a particular variable (mental illness) might have on homelessness. As the causal or in­fluencing characteristic, mental illness is the inde­pendent variable. The variable that they were try­ing to explain, homelessness, is the dependent variable.

According to the hypothesis, homelessness is not typically the result of mental illness. As shown in figure 2-1, causal logic involves the relation­ship between a condition or variable and a partic­ular consequence where one event leads to an­other. Under causal logic, the display of Black Panther bumper stickers on ones car may be di­rectly related to or produce a greater likelihood of receiving a traffic ticket.

A correlation exists when a change in one varia­ble coincides with a change in the other. Correla­tions are an indication that causality may be pres­ent; they do not necessarily indicate causation. For example, data indicate that working mothers are more likely to have- delinquent children than are mothers who do not work outside the home. This correlation is actually caused by a third vari­able: family income. Lower-class households are more likely to have a full-time working mother; at the same time, delinquency rates are higher in this class than in other economic levels. Conse­quently, while having a mother who works out-

PART ONE ♦ THE^vSOCIOLOGICAL PERSPECTIVE