Global Sourcing & Procurement

Chapter 5
Strategic Sourcing Process and Market Engagement

Post Graduate Program in International Business
Global Sourcing & Procurement   •   Post Graduate

Strategic Sourcing Process and Market Engagement

Introduction

Strategic sourcing is the disciplined process through which an organisation identifies business requirements, studies supply markets, designs a sourcing strategy, engages potential suppliers, evaluates alternatives, negotiates commercial and operational terms, and converts the selected option into measurable business value. It differs from routine purchasing because it integrates procurement decisions with corporate strategy, risk management, operations, finance, technology, sustainability and international business considerations.

In global markets, sourcing decisions are affected by exchange-rate movements, trade restrictions, logistics capacity, geopolitical risk, labour standards, intellectual-property protection, taxation, cultural differences and supplier financial resilience. A low quoted price may therefore be inferior to a higher price that provides greater continuity, quality, flexibility and lifecycle value.

The strategic sourcing process is best understood as a controlled decision cycle rather than a single tender event. It begins with a clear definition of need and continues through contract implementation, supplier performance management and benefits realisation. The quality of an award depends not only on the quality of bids but also on the quality of the requirements, market analysis, evaluation model and governance surrounding the decision.

Learning Objectives

After studying this chapter, the learner should be able to:

  1. Explain the strategic sourcing cycle and distinguish it from transactional purchasing.
  2. Translate business needs into objective, measurable sourcing requirements.
  3. Conduct market intelligence and assess supply-market attractiveness and risk.
  4. Select and design appropriate RFIs, RFPs, RFQs and e-auctions.
  5. Construct defensible bid-evaluation and total-cost models.
  6. Recommend suppliers using commercial, technical, risk, ethical and strategic criteria.
  7. Manage award, transition, implementation and benefits realisation.
  8. Critically evaluate the limitations, governance requirements and digital developments associated with sourcing.

1. The Strategic Sourcing Architecture

A robust sourcing process links five levels of decision-making:

  • Business strategy: What competitive or organisational outcome is required?
  • Category strategy: How does the category contribute to that outcome?
  • Sourcing strategy: Which market, commercial model and supplier configuration should be used?
  • Transaction and contract: Which supplier should receive the award and under what terms?
  • Performance and value realisation: Has the award delivered the expected benefits?

The process should be iterative. Market evidence may reveal that the original specification is unnecessarily restrictive; supplier dialogue may identify a better technical solution; and implementation experience may require a revised category strategy.

Strategic sourcing process Definerequirements Analysemarket Engagesuppliers Evaluateand award Implement andrealise benefits Learning, performance data and continuous improvement Strategic sourcing cycle
Strategic sourcing process from requirements to benefits realization
Figure: Strategic sourcing process from requirements to benefits realization

Figure: Strategic sourcing as a connected cycle rather than a one-time tender.

A useful governance principle is fit for purpose. A low-value, standardised purchase may require a short RFQ and price comparison. A multinational technology implementation may require market sounding, a detailed RFP, demonstrations, negotiation, cybersecurity review, transition planning and executive approval.

2. Requirements Definition and Category Framing

Poor requirements create poor competition. If requirements are vague, suppliers price different assumptions; if they are excessively prescriptive, innovation and competition may be excluded. Requirements should therefore describe the business outcome and necessary constraints while avoiding unjustified dependence on a particular supplier or brand.

A requirements document normally includes:

  • business purpose and expected outcomes;
  • scope, locations, volumes and demand profile;
  • mandatory technical, legal, safety and regulatory requirements;
  • functional and performance requirements;
  • service-level measures and remedies;
  • implementation, transition and training requirements;
  • data, cybersecurity and intellectual-property requirements;
  • sustainability, labour and responsible-sourcing expectations;
  • contract duration, pricing structure and key assumptions.

Requirements should distinguish must-have criteria from desirable criteria. A mandatory requirement should be objectively testable and linked to a legitimate business, legal or risk need. Requirements should also identify the baseline against which benefits will be measured. For example, “reduce average order-to-delivery time from 12 to 8 days while maintaining a 98% on-time delivery rate” is more useful than “improve delivery performance.”

Stakeholder alignment

Strategic sourcing is cross-functional. Procurement should involve users, operations, engineering, finance, legal, information security, compliance, sustainability and regional representatives where appropriate. A stakeholder map clarifies who owns the requirement, who approves it, who provides technical input and who will operate the resulting contract.

The sourcing team should challenge demand before going to market. Demand management questions include whether the requirement can be eliminated, standardised, consolidated, substituted, redesigned or fulfilled through an internal capability. This is often more valuable than negotiating a small price reduction after demand has been fixed.

3. Market Intelligence and Sourcing Strategy

Market intelligence converts an internal requirement into an informed view of external possibilities. It should examine both the supply market and the organisation’s position within it.

Important research dimensions include:

  • number, capability and geographic distribution of suppliers;
  • market concentration and barriers to entry;
  • capacity, lead times and production constraints;
  • cost drivers such as materials, energy, labour, freight and finance;
  • technology maturity and substitution opportunities;
  • supplier financial health and ownership structure;
  • trade rules, tariffs, sanctions and local-content requirements;
  • country, logistics, climate and geopolitical risks;
  • industry standards and likely innovation pathways.

Sources may include supplier websites and disclosures, trade associations, industry databases, customs data, analyst research, technical literature, interviews, site visits and prior organisational data. Intelligence should be triangulated: a supplier’s marketing claim is not equivalent to independently verified capability.

Category and supply-market analysis

A category may be analysed by spend, demand, specification, supplier base, risk and strategic importance. The Kraljic portfolio logic is commonly used to distinguish routine, leverage, bottleneck and strategic categories. Its value is not mechanical classification; rather, it encourages managers to match sourcing effort and supplier relationship design to supply risk and business impact.

For example:

Category conditionTypical sourcing emphasis
Low business impact, low supply riskSimplification, catalogues and automation
High business impact, low supply riskCompetition, aggregation and negotiation
Low business impact, high supply riskSupply continuity, alternatives and inventory planning
High business impact, high supply riskJoint planning, executive governance and resilience

The sourcing strategy should specify the number of suppliers, geographic footprint, contract duration, pricing mechanism, allocation model, relationship approach and risk mitigations. A single global supplier may yield scale but create concentration risk. Multiple regional suppliers may reduce disruption exposure but increase coordination and qualification costs.

4. Choosing the Market-Engagement Instrument

Request for Information (RFI)

An RFI is used to understand supplier capability, market structure, technical alternatives and indicative commercial models before a formal competition. It should not be used to obtain binding prices unless the process explicitly provides for that purpose. An RFI can ask about capacity, certifications, implementation approach, geographic coverage, sustainability practices and relevant experience.

The RFI is especially useful when the organisation does not yet know what solutions exist. It should be transparent and should not give one supplier an unfair advantage in a subsequent competition. Material information learned from one participant should normally be shared with all invited bidders, subject to confidentiality obligations.

Request for Proposal (RFP)

An RFP is appropriate when suppliers can propose different technical, service or commercial solutions. It should define the problem, outcomes, constraints, response format, evaluation criteria, timetable, contract assumptions and rules for clarification. Excessively detailed specifications can convert an RFP into an RFQ and prevent suppliers from offering innovation.

The RFP should make clear which terms are negotiable, which are mandatory, how alternatives will be evaluated and whether presentations, demonstrations or best-and-final offers will be used.

Request for Quotation (RFQ)

An RFQ is appropriate for a clearly specified, standardised requirement where price and defined commercial conditions are central. To make quotations comparable, the RFQ must state quantities, delivery points, currency, Incoterms where relevant, taxes, validity period, packaging, payment terms and quality requirements.

E-auctions

An e-auction is a digital price-competition mechanism in which qualified suppliers submit successive bids under predetermined rules. It can be effective for standardised goods or services with several capable suppliers and transparent specifications. It is unsuitable where value depends heavily on innovation, relationship quality, solution design or unquantified lifecycle risk.

Auction governance should define eligibility, bid decrement rules, duration, extensions, visibility of ranking or bids, reserve prices, audit records and post-auction validation. The lowest auction bid is not automatically the best economic outcome; abnormal bids, specification compliance and total cost must still be reviewed.

5. Bid Evaluation and Supplier Selection

Evaluation must be designed before bids are opened. Predetermined criteria reduce bias and make the award defensible. Common criteria include technical compliance, total cost, quality, delivery, implementation capability, cybersecurity, sustainability, financial stability, innovation and risk.

Weighted scoring

A weighted scoring model converts multiple criteria into a structured comparison. If criterion scores are normalised to a common scale, the overall score is:

Sj = ∑i=1n wi rij

where Sj is the total score for supplier j, wi is the weight of criterion i, rij is supplier j’s rating on criterion i, and n is the number of criteria. The weights should sum to 1, or 100%, and all ratings must use the same defined scale. The model assumes that criteria can reasonably be represented on a common scale and that weighted additivity is acceptable for the decision.

For example, suppose three suppliers are assessed using cost (40%), technical capability (30%), implementation (20%) and sustainability (10%), with ratings from 0 to 100:

SupplierCostTechnicalImplementationSustainabilityTotal
A9075806081.5
B7892858884.2
C9570725579.4

For Supplier B, the score is 0.40×78 + 0.30×92 + 0.20×85 + 0.10×88 = 84.2. Supplier B ranks first despite not having the highest cost rating because its technical and implementation strengths are more valuable under the stated weights.

Weighted scoring has limitations. Scores may be subjective, weights may conceal managerial preferences, and compensability may be inappropriate. A critical cybersecurity failure, for example, should not be offset by a low price. Such conditions should be treated as pass/fail gates or minimum thresholds before weighted scoring.

Total cost of ownership

Evaluation should consider all material costs over the relevant decision horizon. A simplified total-cost model is:

TCO = P + F + L + O + M + R − V

where P is purchase price, F is freight and logistics cost, L is duties, taxes and fees, O is operating cost, M is maintenance and support cost, R is quantified risk or expected loss, and V is residual or disposal value. All terms must use the same currency and time basis. The model is applicable when cost components can be estimated reliably; uncertain components should be shown as ranges or scenarios rather than false precision.

If costs occur at different times, present value may be used:

PV = Ct ÷ (1 + r)t

where Ct is the cash flow at time t, r is the period discount rate, and PV is its present value. The period and discount rate must be consistent—for example, annual cash flows require an annual rate. Taxes, inflation, foreign exchange and financing assumptions should be documented.

Risk cost can be estimated as expected loss when probabilities and impacts are sufficiently credible:

Expected loss = ∑ pk Ik

where pk is the probability of risk event k and Ik is its financial impact. This is not a prediction that the loss will occur; it is a decision-support estimate. Low-probability catastrophic events may require scenario analysis, insurance and continuity planning rather than reliance on expected value alone.

Due diligence and negotiations

Due diligence verifies the claims that influenced the evaluation. It may include financial statements, references, factory or service-site visits, quality records, sanctions screening, beneficial-ownership checks, cybersecurity assessments, modern-slavery controls, environmental permits and insurance evidence.

Negotiation should be based on interests, facts and a clear approval mandate. Important subjects include pricing and indexation, volume commitments, payment, service levels, warranties, liability, intellectual property, data use, audit rights, change control, termination, business continuity and dispute resolution. International contracts require careful treatment of governing law, jurisdiction, currency, Incoterms, tax exposure and anti-corruption obligations.

6. Award, Contracting and Implementation

The award decision should be documented through an evaluation report that records the process, criteria, scores, clarifications, deviations, risks, approvals and rationale. Unsuccessful suppliers should receive appropriate feedback without revealing confidential competitor information.

Contracting converts the commercial intention into enforceable commitments. A contract should align scope, pricing, service levels, governance, reporting, remedies and incentives. Ambiguous statements of work create disputes even when the sourcing event was well managed.

Implementation should begin before contract signature for complex categories. A transition plan may include:

  1. mobilisation governance and named workstream owners;
  2. data, systems and master-data preparation;
  3. inventory and order cutover arrangements;
  4. workforce, training and change-management activities;
  5. quality validation and pilot testing;
  6. supplier onboarding and compliance checks;
  7. contingency and escalation procedures;
  8. acceptance criteria and go-live approval.

A contract-management plan should define key performance indicators (KPIs), reporting frequency, meeting cadence, issue escalation, continuous-improvement commitments and review rights. Typical KPIs include on-time-in-full delivery, defect rate, response time, invoice accuracy, savings realised, emissions intensity and corrective-action closure.

7. Benefits Realisation

A sourcing award is an expected benefit, not a realised benefit. Benefits should be baselined, assigned to accountable owners and tracked after implementation. Common benefit categories include price reduction, cost avoidance, demand reduction, working-capital improvement, quality improvement, risk reduction, innovation and service enhancement.

Savings governance must distinguish among:

  • price savings: reduction from a validated prior price at comparable volume and specification;
  • cost avoidance: prevention of an documented future increase;
  • demand savings: financial effect of using less or changing the requirement;
  • cashable benefits: benefits that reduce actual expenditure or release cash;
  • non-cash benefits: operational or risk improvements that may not appear directly in the budget.

For a simple price-saving baseline, the value may be estimated as:

Savings = (Baseline unit price − New unit price) × Actual quantity

The calculation assumes comparable specification, quantity, delivery terms, currency and time period. If those conditions differ, the baseline must be normalised or the result reported as an estimate. Finance validation is important because procurement-reported savings can otherwise overstate organisational value.

Benefits realisation should also monitor unintended consequences. A lower unit price accompanied by higher defects, expedited freight or inventory may reduce total value. Balanced scorecards and periodic supplier reviews help connect commercial outcomes to operational performance.

8. Governance, Ethics and Regulatory Considerations

Strategic sourcing exposes organisations to conflicts of interest, collusion, bribery, discrimination, data leakage and unfair treatment of suppliers. Governance controls should include segregation of duties, conflict declarations, approved evaluation committees, controlled communications, secure bid systems, audit trails and documented approvals.

Ethical sourcing extends beyond compliance with local law. Organisations should assess forced labour, child labour, unsafe conditions, excessive working hours, discrimination, environmental harm and corruption in the supply chain. Contractual commitments are insufficient without risk-based verification, supplier capability-building and credible remediation processes.

Competition law is relevant to information sharing, bid coordination, market allocation and supplier discussions. Procurement teams should avoid exchanging competitively sensitive information among bidders and should obtain legal advice where market concentration or collaborative arrangements create concern. Sanctions, export controls, data-protection rules and public-procurement obligations may apply across borders.

9. Technology, AI and Contemporary Developments

Digital procurement platforms support supplier discovery, electronic tendering, workflow approvals, spend analysis, contract repositories and performance dashboards. Data quality remains a limiting factor: inconsistent supplier names, missing specifications and unreliable historical prices can produce misleading analytics.

AI can assist with classification, document comparison, clause extraction, anomaly detection, supplier-risk monitoring and scenario analysis. However, AI-generated recommendations require human validation. Risks include biased training data, hallucinated facts, confidentiality breaches, opaque scoring and automation bias. Organisations should control access to commercially sensitive bids, retain decision records and ensure that accountable managers—not an unreviewed model—make award decisions.

Contemporary sourcing increasingly incorporates resilience and sustainability. Climate disruption, pandemics, cyberattacks and geopolitical fragmentation have shifted attention from lowest cost toward optionality, visibility, regional capacity, inventory strategy and recovery capability. Circular-economy models, supplier decarbonisation, product traceability and responsible minerals are also becoming material evaluation factors.

Applied Case: Global Components Sourcing (Illustrative)

Background

A fictional industrial-equipment manufacturer purchases precision control modules from one supplier in a single country. Annual spend is $12 million. The incumbent offers competitive pricing but has experienced capacity constraints and a six-week disruption caused by a localised natural disaster.

Problem

Operations wants continuity and shorter lead times, while finance seeks savings. Engineering is concerned that changing suppliers could affect certification and product reliability. The sourcing team must avoid treating resilience as an unpriced aspiration.

Analysis

The team defines mandatory requirements for regulatory certification, defect performance, cybersecurity and technical interchangeability. It conducts an RFI with eight suppliers and finds four technically credible suppliers in three regions. Market research shows that semiconductor availability and specialised testing capacity, rather than assembly labour, are the principal cost and lead-time drivers.

The team develops two scenarios: a single global supplier with volume discounts, and a dual-source model with regional capacity. The second scenario has a higher unit price but reduces concentration risk and permits emergency allocation. TCO includes price, qualification, freight, inventory, quality costs and a quantified disruption exposure. Probabilities are presented as ranges because disaster data are uncertain.

Sourcing approach and solution

An RFP is issued to four qualified suppliers. The evaluation uses pass/fail gates for certification and cybersecurity, followed by weighted criteria: TCO 40%, technical capability 25%, continuity 20%, implementation 10% and sustainability 5%. Supplier X ranks first on price but fails to provide adequate recovery capacity. Suppliers Y and Z are selected as primary and secondary sources after site validation and negotiation.

The contract allocates 70% of normal demand to Y and 30% to Z, with the ability to shift volumes during disruption. It includes capacity reservations, quality thresholds, audit rights, index-based pricing for major inputs, emergency logistics provisions and a joint continuity plan.

Outcome

The dual-source arrangement reduces expected disruption exposure and improves average lead time, although the quoted unit price is 3% higher than the former incumbent price. After six months, defect performance remains within target, total delivered cost is lower than the original scenario analysis projected, and the business has a validated recovery option.

Learning points

The case demonstrates that strategic sourcing evaluates value rather than price alone. It also shows why requirements, market intelligence, scenario analysis, technical gates, contract design and post-award measurement must be integrated. Resilience is valuable only when it is translated into capacity, rights, processes and measurable performance.

Challenges and Limitations

Strategic sourcing models cannot eliminate uncertainty. Supplier data may be incomplete, probabilities may be contested, and weighted scores can give an appearance of objectivity without removing judgement. International comparisons are complicated by currency volatility, different accounting practices, labour costs, infrastructure quality and legal enforceability.

Time pressure can lead teams to skip market analysis or due diligence. Excessive process can also be counterproductive, discouraging smaller or innovative suppliers. The appropriate response is proportional governance: more scrutiny for high-risk, high-value and strategically important categories, and simpler processes for routine purchases.

A further limitation is organisational behaviour. Users may resist standardisation, incumbent suppliers may exploit switching costs, and internal stakeholders may manipulate requirements to favour a preferred supplier. Independent challenge, transparent criteria and executive sponsorship help protect the integrity of the process.

Best-Practice Checklist

  • Begin with the business outcome, not a predetermined supplier or product.
  • Validate and challenge demand before specifying supply.
  • Separate mandatory gates from weighted preferences.
  • Use market intelligence to test assumptions and design competition.
  • Match RFI, RFP, RFQ or auction to the nature of the requirement.
  • Evaluate total cost, risk and lifecycle value, not quoted price alone.
  • Predefine criteria, weights, scoring rules and approval rights.
  • Verify supplier claims through proportionate due diligence.
  • Protect confidentiality, fairness and competition throughout the process.
  • Begin transition planning before award and assign benefit owners.
  • Validate savings and monitor operational, ethical and resilience outcomes.
  • Review the category after implementation and feed learning into the next cycle.

Chapter Summary

Strategic sourcing is a structured, evidence-based cycle linking business requirements to market intelligence, supplier engagement, evaluation, award, implementation and benefits realisation. Requirements must be outcome-oriented, measurable and aligned across stakeholders. Market analysis informs the choice of supplier model, geographic footprint, contract duration and risk response. RFIs explore capability, RFPs invite solution proposals, RFQs compare standardised quotations and e-auctions create controlled price competition where conditions are suitable.

Defensible supplier selection combines mandatory compliance gates with transparent evaluation criteria. Weighted scoring can structure trade-offs, while total-cost and present-value analysis prevent narrow focus on initial price. Due diligence, ethical controls, competition safeguards and international contract considerations are essential. Finally, the award is only the beginning: implementation, performance management, finance validation and continuous improvement determine whether expected benefits become organisational value.

Key Terms

Strategic sourcing: An integrated process for obtaining external goods or services in support of organisational strategy.

Category strategy: A plan for managing a group of related purchases and their supply market.

Market intelligence: Structured information about suppliers, economics, technology, capacity and risk.

RFI: Request for Information used to explore market capability and possible solutions.

RFP: Request for Proposal used when suppliers may offer different solutions or approaches.

RFQ: Request for Quotation used for defined and comparable requirements.

E-auction: A digital bidding event in which qualified suppliers compete under stated rules.

Total cost of ownership: The complete relevant cost of acquiring, operating, supporting and disposing of an option.

Weighted scoring: A multi-criteria evaluation method using criterion weights and supplier ratings.

Mandatory gate: A pass/fail requirement that cannot be offset by strength in another criterion.

Due diligence: Verification of supplier capability, integrity, financial health and compliance.

Supplier concentration: The degree to which supply depends on a small number of suppliers.

Resilience: The ability of a supply network to prepare for, respond to and recover from disruption.

Incoterms: Standardised international trade terms allocating delivery responsibilities, costs and risks.

Service-level agreement: Contractual definition of measurable service performance and remedies.

Benefits realisation: The process of verifying that planned financial and operational benefits occur.

Cost avoidance: Prevention of an expected future cost increase.

Responsible sourcing: Procurement that addresses social, environmental, ethical and governance impacts.

Evaluation governance: Controls that ensure fair, consistent, auditable and authorised supplier decisions.

Review Questions

Short Answer Questions

  1. Why is strategic sourcing broader than transactional purchasing?
  2. Distinguish an RFI, an RFP and an RFQ.
  3. What is the purpose of a mandatory evaluation gate?
  4. Identify four components that may be included in total cost of ownership.
  5. Why should benefits be baselined and assigned to accountable owners?

Long Answer Questions

  1. Explain the stages of the strategic sourcing cycle and show how information should flow between them.
  2. Discuss how market intelligence influences supplier configuration, contract duration and risk mitigation.
  3. Explain the strengths and limitations of weighted scoring in supplier evaluation.
  4. Analyse the ethical, regulatory and governance risks in international sourcing.
  5. Describe how a sourcing team should manage implementation and benefits realisation after award.

Analytical / Application Questions

  1. A buyer must source a standardised component from five qualified suppliers. Design an RFQ and explain which information is necessary to make quotations comparable.
  2. A supplier has the lowest price but weak business-continuity capability, while a second supplier costs 4% more and offers regional backup. Develop a decision framework using TCO, risk and scenario analysis.
  3. Construct a weighted evaluation model for an international technology-services RFP. Justify the criteria, weights, mandatory gates and post-award KPIs.

Multiple Choice Questions with Answers

Question 1

Which instrument is most appropriate for learning about supplier capabilities before designing a formal competition?

A. Request for Information (RFI)

B. Request for Quotation (RFQ)

C. Purchase order

D. E-auction

Correct Answer: A. Request for Information (RFI)

Question 2

In a weighted scoring model, what should normally be true of all criterion weights?

A. Each weight must exceed 50%

B. The weights should sum to 1 or 100%

C. All weights must be identical

D. Weights should be expressed only in currency

Correct Answer: B. The weights should sum to 1 or 100%

Question 3

Using the chapter’s scoring example, what is Supplier B’s total score?

A. 78.0

B. 81.5

C. 84.2

D. 92.0

Correct Answer: C. 84.2

Question 4

Which item is most appropriately treated as a mandatory gate rather than an offsetting weighted preference?

A. Preferred reporting format

B. Optional training material

C. Minor packaging preference

D. Required cybersecurity compliance

Correct Answer: D. Required cybersecurity compliance

Question 5

Which sourcing instrument is generally best suited to a clearly specified, standardised requirement?

A. RFQ

B. RFI

C. Innovation workshop

D. Unstructured negotiation

Correct Answer: A. RFQ

Question 6

In the simplified TCO equation, which term represents quantified risk or expected loss?

A. P

B. L

C. R

D. V

Correct Answer: C. R

Question 7

Why may a dual-source strategy be selected even when its unit price is higher?

A. It eliminates the need for contracts

B. It can reduce concentration and disruption risk

C. It guarantees the lowest quoted price

D. It removes all quality requirements

Correct Answer: B. It can reduce concentration and disruption risk

Question 8

Which activity is part of supplier due diligence?

A. Ignoring ownership structure

B. Verifying financial health and compliance

C. Allowing undisclosed bid changes

D. Removing audit rights

Correct Answer: B. Verifying financial health and compliance

Question 9

What does benefits realisation primarily require after a sourcing award?

A. Ending performance measurement

B. Tracking validated outcomes against a baseline

C. Replacing all suppliers immediately

D. Measuring only the quoted unit price

Correct Answer: B. Tracking validated outcomes against a baseline

Question 10

Which condition makes an e-auction least appropriate?

A. Several qualified suppliers exist

B. The specification is standardised

C. Value depends heavily on innovation and solution design

D. Auction rules can be defined in advance

Correct Answer: C. Value depends heavily on innovation and solution design

Global Sourcing & Procurement
Chapter 5 of 15