3. If possible, verify the causes through observation or by controlling variables directly.

TABLE 8.5 The Seven-Step Method Source: Reprinted with permission from M. Gaudard, R. Coates, and L. Freeman, “Accelerating Improvement,” Quality Progress 24, no. 10, October 1991, p. 82.

(continued)

M 9

8 7

6 5

4 3

2 1

T W T F S S M T W T F S S M T W T F S S Day of week Percent who waited FIGURE 8.15 Run Chart of Percent of Customers Waiting More Than One Minute to Be Seated Source: Reprinted with permission from M. Gaudard, R. Coates, and L. Freeman, “Accelerating Improvement,” Quality Progress 24, no. 10, October 1991, p. 83.

Chapter 8 Process Improvement 201 Step 4 Implement a Solution