Remote Sensing Vegetation and Water Indices: Understanding NDVI, NDMI, NDWI and Their Applications

 

Introduction

The Quality-Cum-Cost Based Selection (QCBS) method is widely used for procuring consultancy and professional services in public sector projects, especially where technical quality is as important as cost. QCBS balances these two aspects by assigning predefined weightages to both the technical and financial components of the bid.

A critical part of the QCBS process is the evaluation and preparation of a comparative statement of bids, which helps determine the most advantageous bidder through a transparent, defensible methodology. This article outlines how QCBS bids are evaluated and how a comparative statement is prepared to finalize contract award.

---

1. Overview of the QCBS Process

Under QCBS, bidders submit two separate envelopes:

• Envelope I: Technical Proposal

• Envelope II: Financial Proposal

These are opened and evaluated in two distinct stages:

1. Technical Evaluation

2. Financial Evaluation (only for technically qualified bidders)

The final score is calculated using a weighted formula such as:

• Technical Proposal = 70% weight

• Financial Proposal = 30% weight

---

2. Evaluation Process in Detail

A. Technical Evaluation

A committee evaluates each technical proposal based on pre-established criteria defined in the RFP (Request for Proposal), such as:

• Firm's experience and past performance (e.g., 20 marks)

• Approach and methodology (e.g., 25 marks)

• Qualifications of key personnel (e.g., 40 marks)

• Work plan and timeline (e.g., 15 marks)

Each bid is scored out of 100. A minimum qualifying mark (e.g., 70/100) is usually required to proceed to financial evaluation.

The technical score for each qualifying bidder is then normalized using:

$$T_n = \frac{T_i}{T_{max}} \times 100$$

Where:

• $T_n$ = Normalized technical score

• $T_i$ = Technical score of the bidder

• $T_{max}$ = Highest technical score among all bidders

---

B. Financial Evaluation

The financial proposals of only technically qualified bidders are opened. The lowest price (L₁) is given a financial score of 100.

Other financial scores are calculated as:

$$F_n = \frac{L_1}{L_i} \times 100$$

Where:

• $F_n$ = Normalized financial score

• $L_1$ = Lowest bid price

• $L_i$ = Price of the i-th bidder

---

C. Final Combined Score

The final score for each bidder is computed as:

$$S = T_n \times w_t + F_n \times w_f$$

Where:

• $w_t$ = weight of technical score (e.g., 0.7)

• $w_f$ = weight of financial score (e.g., 0.3)

• $S$ = final weighted score

The bidder with the highest score (S) is ranked first and recommended for contract award.

---

3. Preparing the Comparative Statement

A comparative statement summarizes the evaluation results and supports the selection process. It typically includes:

Table 1: Technical Evaluation Summary

Bidder	Technical Marks	Normalized Technical Score (Tn)	Qualified?
A	85	100.00	Yes
B	78	91.76	Yes
C	68	-	No

Table 2: Financial Bids

Bidder	Price Quoted (INR)	Financial Score (Fn)
A	₹1,200,000	100.00
B	₹1,500,000	80.00

Table 3: Final Combined Scores (Example: 70:30 weightage)

Bidder	Tn	Fn	Final Score (S)	Rank
A	100	100	100.00	1
B	91.76	80.00	87.23	2

The comparative statement should be supported by:

• Evaluation Committee signatures

• Clarifications (if any) from bidders

• Observations on disqualified proposals

---

4. Common Mistakes to Avoid

• Mixing technical and financial evaluations prematurely

• Using non-disclosed evaluation criteria

• Improper normalization of scores

• Lack of justification for disqualification

All scoring, normalization, and final selection must be fully transparent and auditable.

---

5. Importance in Public Procurement

A comparative statement under QCBS not only determines the most suitable bidder but also ensures:

• Accountability and objectivity in selection

• Value-for-money in public spending

• Compliance with procurement regulations and audit standards

---

Conclusion

The evaluation and comparative statement in a QCBS tender contract are crucial documents that balance technical excellence with financial discipline. A well-structured, criteria-based evaluation followed by a transparent comparative statement ensures the most competent and cost-effective consultant is selected for critical assignments in infrastructure, irrigation, and public services.

With increasing adoption of performance-based and quality-sensitive contracts, QCBS and its evaluation framework offer a best-practice model for responsible public procurement.