How are weighted scores calculated in Cotiss?

Evaluation Criteria

Weighted scoring in a procurement evaluation is a method to assess and compare vendor proposals systematically and objectively. When evaluations involve two levels of criteria — main criteria and their respective sub-criteria — the calculations ensure that both levels are appropriately weighted based on their relative importance. This ensures decisions align with your organisation’s priorities.

Here’s a detailed description of how the calculations are created and structured in Cotiss:

1. Define and Structure Evaluation Criteria

• Main Criteria: These are the high-level areas of evaluation, typically based on organizational priorities such as Cost, Quality, Delivery, or Technical Capability.
• Sub-Criteria: These are the detailed factors under each main criterion. For instance:
  • Cost → Upfront Cost, Ongoing Costs.
  • Quality → Durability, Reliability.

2. Assign Weights to the Main Criteria

• Determine the relative importance of each main criterion based on organizational priorities.
• Assign weights to each main criterion. For example:
  • Cost = 40%
  • Quality = 35%
  • Delivery Time = 25%

3. Distribute Weights Among Sub-Criteria

• Each main criterion’s weight is further distributed among its sub-criteria based on their relative importance within that criterion.
• For example:
  • If Cost = 40% and has two sub-criteria:
    • Upfront Cost = 30% of the 40% (0.3 × 0.4 = 12% total weight).
    • Ongoing Costs = 10% of the 40% (0.1 × 0.4 = 4% total weight).
• The total sub-criteria weights under a main criterion must equal that criterion’s weight.

4. Score Vendors on Sub-Criteria

• Vendors are evaluated for each sub-criterion using a defined scale, such as:
  • 1 to 5, where 1 = Poor and 5 = Excellent.
  • 1 to 10, for finer granularity.
• Example:
  • Vendor A scores 8/10 on Upfront Cost and 7/10 on Ongoing Costs.

5. Calculate Weighted Scores for Each Sub-Criterion

• Multiply the vendor’s score for each sub-criterion by its total weight (main criterion weight × sub-criterion weight).
• Formula:
  • 

Example:

For Cost (40%) with two sub-criteria:

• Upfront Cost (12%): Vendor A scores 8/10.
  • 0.4 x 0.3 x 8 =0.96
• Ongoing Costs (4%): Vendor A scores 7/10.
  • 0.4 x 0.1 x 7 = 0.28

6. Aggregate Scores for Main Criteria

• Sum the weighted scores of all sub-criteria under each main criterion to get the vendor’s total score for that criterion.
• Formula:
  • 

Example:

• For Cost: Cost Score = 0.96(Upfront Cost) + 0.28(Ongoing Cost) = 1.24

7. Calculate the Vendor’s Final Weighted Score

• Sum the scores of all main criteria to determine the vendor’s overall performance.
• Formula:
  • 

Example:

For Vendor A:

• Cost = 1.24 (0.96 + 0.28)
• Quality = 0.95 (0.63 + 0.32)
• Delivery = 0.48 (0.3 + 0.18)

Total Weighted Score for Vendor: 0.96 + 0.28 + 0.63 + 0.32 + 0.3 + 0.18 = 2.67