When using the factor-rating method to assist in a decision-making process, it is important to assign weights to each criterion beforescoring the supplier options, thereby eliminating possible manipulation of the process.

Sure, let's break down the process step by step:

1. Identify Criteria: First, determine the criteria that are important for the decision-making process. These could include factors such as cost, quality, delivery time, reliability, etc.

2. Assign Weights: Assign a weight to each criterion based on its importance. The weights should reflect the relative importance of each criterion in the overall decision. For example, if cost is more important than delivery time, it should have a higher weight.

3. List Supplier Options: Identify the supplier options that you are considering.

4. Score Each Supplier: For each supplier, assign a score for each criterion. The score should reflect how well the supplier meets that particular criterion.

5. Calculate Weighted Scores: Multiply the score for each criterion by the weight assigned to that criterion. This will give you a weighted score for each criterion for each supplier.

6. Sum the Weighted Scores: Add up the weighted scores for each supplier to get a total score for each supplier.

7. Compare and Decide: Compare the total scores of all the suppliers. The supplier with the highest total score is typically the best choice, based on the criteria and weights you have assigned.

By following these steps, you ensure a structured and objective decision-making process, minimizing the risk of manipulation.