Social Research Methods: Qualitative and Quantitative Approaches

STRATEGIES OF RESEARCH DESIGN

evidence that supports a hypothesis differently from
evidence that opposes it: They give negative evi-
dence more importance. The idea that negative evi-
dence is critical when evaluating a hypothesis comes
from the logic of disconfirming hypotheses.^16 It is
associated with Karl Popper’s idea of falsification

and with the use of null hypotheses (see later in this

section).

Recall the preceding discussion of proof.

We never prove a hypothesis; however, we can dis-

prove it. With supporting evidence, we can say only

that the hypothesis remains a possibility or that

it is still being considered. Negative evidence is

more significant. With it, the hypothesis becomes

“tarnished” or “soiled” because a hypothesis makes

predictions. Negative and disconfirming evidence

shows that the predictions are wrong. Positive or

confirming evidence for a hypothesis is less criti-

cal because various alternative hypotheses may

make the same prediction. When we find confirm-

FIGURE 3 How the Process of Hypotheses Testing Operates over Time

Test

Test

Test

Test

1 2 3 4 5

1 3 2 4 5

9 8 10 11

6

7 8

Reject Remain under

Consideration

Two of the original five hypotheses

are rejected.

A new one is developed.

There are five possible hypotheses.

2 5 4 6

Reject Remain under

Consideration

Two hypotheses are rejected.

Two new ones are developed.

4 7 6 8 9

Reject Remain under

Consideration

Three hypotheses are rejected.

A new one is developed.

Reject Remain under

Consideration

One hypothesis is rejected.

Two new ones are developed.

1980

1970

1990

2000

2010

Logic of disconfirming hypothesis The logic for the

null hypothesis based on the idea that confirming

empirical evidence makes a weak case for the exis-

tence of a relationship; instead of gathering support-

ing evidence, testing that no relationship exists

provides more cautious, indirect support for its pos-

sible existence.