Cause and Effect Chain Analysis Techniques

Cause and Effect Chain Analysis

• A cause-and-effect analysis generates hypotheses about the causes and effects of problems.
• A Cause & Effect Chain (CEC) analysis diagram is a structured method to express hypotheses about the causes of a problem or why something isn't working as intended.
• It helps focus attention on the process where a problem occurs and uses facts to pinpoint the actual causes.
• It doesn't replace empirical testing; it identifies possibilities, not definitive root causes.

How to Use Cause & Effect Chain Analysis

• Step 1: Negate the problem's goal and write it in the target problem. Brainstorm likely causes and categorize them.
• Step 2: Continue brainstorming and categorize causes.
• Step 3: Keep asking "Why?" and "Why else?" for each cause to identify potential root causes.
• Step 4: Use team judgment to select likely causes and eliminate unlikely ones.
• Step 5: Use team judgment to select likely causes and eliminate unlikely ones.
• Step 6: Validate the hypothesis by confirming the likely root cause and implement a solution.
• Step 7: If necessary, go back and test other potential causes.

Example Use Cases

• Example 1 (Food-Related): A wrong diet leads to excessive salt in the blood, which causes high blood pressure, leading to a headache.
• Example 2 (Engineering): A device isn't working (e.g., no light when the switch is turned on). The cause-and-effect chain could lead to a broken switch, a broken light bulb, a cracked socket, or a power spike.
• Other causes might be a filament that has worn out, or a manufacturing issue in the bulb, or a mechanical shock.

Further Analysis

• Chains of Problems: Problems in an engineering system can be interconnected and form chains, with known, hidden, intermediate, and key problems.
• Case Study (Procter & Gamble): The development of a coffee bag to overcome slow extraction resulted in a higher cost due to an increased amount of coffee in the bag.
• Solution (Procter & Gamble): Adding ionite particles to the bag reduces the amount of calcium and magnesium ions from the water. This improves extraction without impacting taste.
• Exercises: Several exercises (e.g., school-children shoulder pain, face mask clouding spectacles, or an EBB that doesn't turn on) require cause-and-effect analysis to identify the root problem.