《DELL_6_SIGMA_GB_TRAINING_6》.ppt

BPI Level IModule 6 - Control Module Objectives: Control Maintain Gains Statistical Process Control, SPC Process Capability Documentation Statistical Validation SPC Shifts Hypothesis Testing (JMP/Statistics/BB Courses) Financial Validation Realized Cost-Benefit Analysis Statistical Process Control Charts Improved Run Chart Tool for monitoring, controlling, and improving processes performance through time Make sure the centering and spread are not changing over time Statistically distinguish between the occurrence of special or common causes of variation Available for both attributes and variables data Decision tree All control charts share a common structure and language Interpret with “rules” Run Chart versus Control Chart Run chart Process behavior through time Both continuous and attribute data No rules for interpreting data Cannot distinguish between special and common causes of variation Control chart Process behavior through time Both continuous and attribute data Statistically based limits and rules for interpreting data Can distinguish between special and common causes of variation Common Format x-axis = time y-axis = count or measurement Plot “connect the dot” Center line = average Upper control limit (3s) Lower control limit (3s) Interpreting Control Charts – Some Guidelines A process is identified as out of control when any of the special conditions indicated by the rules is apparent – see Memory Jogger? p. 45 Common Causes vs Special Causes Common Causes Happen all the time Part of the process Controlled only through process redesign Account for 85% of total process variation Special Causes Happen sometimes Additional to the process Controlled by isolation and elimination Account for 15% of total process variation Documentation Key Differences Finance: Roles and Responsibilities During estimation Agree on financial measures Agree on anticipated financial impact During validation Verify project expenses Verify projected cost benefit 4 hours est