Dispute Avoidance and Resolution

Introduction and context

Construction projects combine technical uncertainty, numerous contractual relationships, regulatory controls, and substantial financial exposure. Delay, defects, payment disagreements, design responsibility, variations, disruption, extensions of time, and termination disputes are therefore common. A dispute is not merely a disagreement: it is usually a disagreement that has crystallised into a claim, been rejected or ignored, and requires an authoritative or negotiated outcome.

Dispute management has two dimensions. Dispute avoidance seeks to prevent disagreements from becoming formal disputes through clear drafting, competent administration, early warning, good records, and collaborative problem-solving. Dispute resolution provides mechanisms for determining or settling disputes when prevention has failed. The appropriate mechanism depends on the contract, governing law, jurisdiction, urgency, technical complexity, value, relationship, confidentiality requirements, enforceability, and cost.

A construction professional need not become a lawyer, but must understand when a matter requires legal advice, how contractual procedures operate, and how project decisions affect later evidence. This chapter examines negotiation, mediation, dispute boards, statutory adjudication, expert determination, arbitration, and litigation as a strategic system rather than as isolated procedures.

Jurisdictional note: The legal effect of these mechanisms varies significantly between jurisdictions. Statutory adjudication, court powers, limitation periods, privilege, arbitration legislation, and enforcement rules must be checked against the applicable law and the actual contract.

Learning objectives

By the end of this chapter, a student should be able to:

1. Distinguish dispute avoidance from dispute resolution and identify common construction disputes.
2. Select an appropriate procedure by evaluating jurisdiction, urgency, evidence, cost, enforceability, and relationships.
3. Explain the roles and limitations of negotiation, mediation, dispute boards, adjudication, expert determination, arbitration, and litigation.
4. Manage notices, records, evidence, procedural fairness, and confidentiality.
5. Compare domestic and cross-border dispute resolution and recommend a proportionate strategy.
6. Evaluate ethical, technological, and governance risks in dispute management.

1. The anatomy of a construction dispute

A dispute commonly develops through the following sequence:

Event → contractual entitlement → notice or claim → assessment or rejection → disagreement → formal procedure → outcome and enforcement.

The event may be an instructed variation, late information, unexpected ground condition, defective work, delayed payment, or alleged breach. The claimant must then connect the event to a contractual or legal entitlement. For example, a delay does not automatically create an entitlement to an extension of time: the contract may require timely notice, proof of critical-path impact, and compliance with specified conditions.

Important categories include:

• Payment disputes: valuation, certification, withholding, set-off, retention, and final account.
• Time disputes: extensions of time, concurrent delay, acceleration, and liquidated damages.
• Defect disputes: workmanship, design responsibility, testing, inspection, and rectification.
• Variation disputes: authority to vary, valuation, omission, and changed scope.
• Disruption and loss-and-expense disputes: reduced productivity, interference, prolongation, and additional site overheads.
• Termination disputes: repudiation, contractual termination, insolvency, and consequences of termination.
• Professional negligence disputes: inadequate design, certification, supervision, or advice.

A useful distinction is between a claim and a dispute. A claim is an assertion of entitlement. It may be accepted, assessed, or negotiated without becoming a dispute. A dispute arises when the claim is expressly rejected, treated as rejected by inaction where the contract permits that conclusion, or otherwise becomes contested. This distinction matters because some dispute clauses activate only after a dispute exists.

2. Dispute avoidance: designing the project to reduce conflict

Avoidance begins before contract award. The employer should define scope, interfaces, site information, procurement responsibilities, risk allocation, payment mechanisms, and decision-making authority. Ambiguous risk transfer does not eliminate risk; it often transfers the cost of later disagreement into legal fees, delay, and damaged relationships.

2.1 Clear contractual architecture

A coherent contract should identify:

• the order of precedence among drawings, specifications, schedules, and amendments;
• design responsibility and review obligations;
• notice periods and prescribed methods of communication;
• valuation and payment procedures;
• extension-of-time and delay analysis requirements;
• variation authority and pricing rules;
• record-keeping responsibilities;
• escalation and dispute-resolution steps;
• governing law, jurisdiction, and language; and
• termination and suspension rights.

Standard forms can improve predictability, but they do not remove the need for project-specific amendments. Poorly coordinated amendments may create contradictory obligations.

2.2 Administration and early warning

Project managers should maintain a live risk and issue register. Each entry should identify the event, date, responsible party, contractual clause, potential effect, required notice, mitigation, and status. Early-warning systems encourage parties to address emerging problems before positions harden.

Effective avoidance practices include:

• regular progress and commercial meetings;
• prompt distribution of accurate minutes;
• contemporaneous site diaries and photographs;
• approval and design-submittal registers;
• change-control procedures;
• clear lines of delegated authority;
• joint inspection and testing protocols; and
• periodic review of programme, cost, safety, and quality risks.

Records should be factual rather than argumentative. A site diary stating “concrete pour stopped at 14:00 because approved drawings were unavailable” is generally more useful than “employer caused another unreasonable delay.”

2.3 Commercial and relational behaviour

A party may possess a legal right yet damage the project by exercising it without considering consequences. Good-faith collaboration does not necessarily replace strict contractual compliance, especially where notices are conditions precedent, but it can support practical solutions. Meetings should separate technical facts, contractual entitlement, quantum, and settlement options. This prevents a disagreement about one issue from contaminating every aspect of project administration.

Figure: A proportionate escalation pathway from early warning to formal adjudication or court proceedings.

3. Negotiation and mediation

3.1 Negotiation

Negotiation is a direct process in which parties, usually through authorised representatives, attempt to reach agreement. It is flexible, private, inexpensive compared with formal proceedings, and capable of producing commercial solutions unavailable to a tribunal—for example, revised sequencing, additional resources, a partial payment, or a future-work arrangement.

Preparation should include an issues list, chronology, contractual analysis, valuation, evidence assessment, authority limits, and a realistic settlement range. Parties should distinguish their position (“we are entitled to the full amount”) from their interests (“we need cash flow and certainty before the next work package”). Separating people from problems and testing assumptions can preserve the working relationship.

Negotiation fails where representatives lack authority, relevant information is withheld, deadlines are used tactically, or one party believes delay will force surrender. A settlement should be recorded in a signed agreement identifying payment, release, confidentiality, tax, continuing obligations, and treatment of unresolved matters.

3.2 Mediation

Mediation introduces an independent, neutral mediator who manages communication but normally does not impose a decision. The mediator may use joint meetings, private caucuses, reality testing, and option generation. The parties retain control over whether to settle.

Mediation is especially valuable where the dispute contains both legal and relational dimensions, or where a continuing project makes a purely win–lose outcome undesirable. It may be less suitable where a party needs an urgent binding decision, refuses to participate meaningfully, or seeks a precedent on a point of law.

Confidentiality and without-prejudice rules are jurisdiction-specific. Participants should clarify whether statements made during mediation can be disclosed, how documents are handled, and when a settlement becomes binding. The mediator must disclose conflicts and remain impartial; a mediator who becomes an advocate compromises the process.

4. Dispute boards

A dispute board is an independent panel appointed during, and sometimes before, project performance. Depending on the contract, it may:

• visit the site and become familiar with progress;
• provide informal opinions or recommendations;
• assist in preventing disputes; and
• issue decisions when a dispute is referred.

A dispute review board generally recommends, while a dispute adjudication board generally issues a decision that has immediate contractual effect, subject to later arbitration or litigation. A combined board may perform both functions. The exact effect depends on the contract and applicable law.

The principal advantage is early, project-specific knowledge. Board members can understand technical context without requiring every fact to be reconstructed years later. The disadvantages include standing costs, potential conflicts, and the risk that informal involvement compromises impartiality. Appointment provisions should address qualifications, independence, replacement, fees, site access, communications, and decision deadlines.

5. Statutory adjudication

Statutory adjudication is a rapid process established by legislation in some jurisdictions, particularly for construction payment and related disputes. Its policy objective is often “pay now, argue later”: cash flow should continue while final rights may be determined subsequently.

A typical process involves a notice of adjudication, appointment of an adjudicator, referral notice, response, reply if permitted, and a decision within a prescribed period. The adjudicator must usually act impartially and within jurisdiction. Natural justice requires that each party has a fair opportunity to present relevant material and respond to significant arguments.

Adjudication is attractive because it is faster and less costly than a full trial or arbitration. However, speed restricts the amount of evidence and time available. Jurisdictional challenges may concern whether a dispute has crystallised, whether notice requirements were met, whether the referral exceeds the dispute, or whether the adjudicator acted outside authority.

Enforcement may occur through court order or summary procedure, depending on the statute. A party dissatisfied with the decision may have a right to commence arbitration or litigation, but must generally comply first unless the decision is invalid or a recognised exception applies. Students must never assume that a contractual adjudication clause can exclude statutory rights.

6. Expert determination

Expert determination is appropriate where the principal issue is technical, professional, or valuation-based. The parties appoint an expert to determine a defined question, such as the adjustment of a price index, the value of work, plant capacity, or whether a defect meets a specified performance standard.

The expert acts on specialist knowledge rather than necessarily applying judicial procedures. The appointment agreement should specify:

• the question to be determined;
• the expert’s qualifications and independence;
• whether the decision is binding or advisory;
• the evidence and inspections permitted;
• procedural timetable;
• correction of manifest errors; and
• allocation of fees.

Expert determination is efficient for narrow technical questions but unsuitable for broad disputes involving credibility, extensive legal interpretation, or multiple parties. An expert who is required to act as an expert must not silently become an arbitrator; the legal duties and available remedies differ.

7. Arbitration

Arbitration is a private adjudicative process in which an arbitrator or tribunal issues an award. It is based on party agreement, usually an arbitration clause, and is governed by the law of the arbitration seat. The seat is a legal concept: it determines the supervisory court and procedural framework, even if hearings occur elsewhere.

Important choices include:

• number and appointment of arbitrators;
• seat and venue;
• governing substantive law;
• institutional or ad hoc administration;
• language;
• applicable rules;
• confidentiality; and
• consolidation or joinder of related contracts.

Arbitration can offer specialist decision-makers, procedural flexibility, privacy, and stronger cross-border enforcement than many court judgments. The New York Convention provides a widely used framework for recognition and enforcement of foreign arbitral awards, subject to national implementation and limited refusal grounds.

Its disadvantages include tribunal and institutional fees, potentially lengthy procedures, limited appeal rights, and difficulties joining parties who did not agree to arbitrate. Multi-contract construction projects are particularly vulnerable to fragmented proceedings: the employer, main contractor, designer, and subcontractors may be bound by different dispute clauses. Drafting should address compatible arbitration agreements, joinder, consolidation, and appointment mechanisms.

The tribunal’s authority derives from the arbitration agreement. Questions of jurisdiction may include validity, scope, arbitrability, and whether a non-signatory is bound. Parties should raise jurisdictional objections promptly because delay may amount to waiver under applicable law or rules.

8. Litigation

Litigation is a public court process controlled by procedural law and judicial case management. It is essential where there is no arbitration agreement, urgent court relief is needed, insolvency or third-party issues are central, or authoritative interpretation and precedent are important.

Courts may provide injunctions, security, declarations, judgments, enforcement orders, and appeals. They may also have compulsory powers over parties, witnesses, and documents. Nevertheless, litigation can be slow, expensive, public, and adversarial. Specialist construction courts or lists may improve case management, but they remain subject to court timetables and jurisdictional rules.

Before commencing proceedings, a claimant must check limitation periods, contractual preconditions, forum clauses, service requirements, and applicable pre-action protocols. Failure to comply may lead to stays, costs penalties, or dismissal. Courts generally expect parties to preserve relevant documents and disclose adverse as well as helpful evidence.

9. Selecting the appropriate mechanism

No mechanism is universally best. A strategic selection evaluates the following factors:

The cheapest procedure is not necessarily the most economical. A low-cost process that produces an unenforceable or incomplete result may increase total cost. Decision-makers should compare expected cost, time, probability of success, business impact, enforceability, and opportunity cost.

A simple strategic model is qualitative rather than mathematical: score each available mechanism against urgency, technical complexity, relationship value, privacy, cross-border enforceability, and procedural formality. Weighting should reflect project priorities, and the scores should support—not replace—professional judgment.

10. Evidence, procedure, and quantum

Successful dispute management depends on proving four connected matters:

1. What happened? Establish the event through records, correspondence, photographs, programmes, instructions, tests, and witness evidence.
2. What obligation or right applies? Identify the contract clause, statute, implied term, or legal principle.
3. What was the consequence? Demonstrate causation, such as critical delay, additional labour, rework, or lost productivity.
4. What remedy follows? Quantify payment, time, damages, specific relief, or another remedy.

Evidence should be preserved contemporaneously. Relevant records may include contract versions, drawings, requests for information, transmittals, meeting minutes, payment records, programmes, schedules, daily reports, resource logs, delivery tickets, testing data, and electronic metadata.

A delay claim often requires a structured comparison between the planned programme and actual progress. The chosen delay-analysis method must suit the available records, contract requirements, project complexity, and period under review. A programme colour bar alone does not prove causation. The analyst must explain logic, criticality, concurrency, mitigation, and the relationship between employer-risk and contractor-risk events.

Quantum evidence may include measured work, invoices, payroll, plant records, overhead allocation, productivity studies, and expert valuation. Damages must be connected to the pleaded breach and supported by reliable records; unsupported global estimates are vulnerable even where some loss clearly occurred.

11. Cross-border and enforcement considerations

International projects add questions of governing law, jurisdiction, language, currency, tax, sovereign immunity, sanctions, evidence location, service, and enforcement. The contract should distinguish:

• governing law: the substantive law applied to rights and obligations;
• seat or forum: the legal location of arbitration or court proceedings; and
• venue: the physical or virtual place of hearings.

These concepts are not interchangeable. A contract may apply the law of one country, select an arbitral seat in another, and hold hearings in a third.

Enforcement analysis should occur before a dispute arises. Identify where the opposing party’s assets are located, whether local courts recognise foreign judgments or awards, and whether public-policy or sovereign-immunity rules may intervene. Interim measures may be required to preserve assets, evidence, or the status quo. Translation and expert evidence can materially increase cost and duration.

Parties should also consider data protection, cybersecurity, export controls, sanctions, and confidentiality. International arbitration is not automatically confidential in every jurisdiction, and remote hearings create risks of unauthorised recording, insecure document exchange, and unequal access to technology.

12. Ethics, governance, and technology

Dispute professionals owe duties of honesty, independence, competence, confidentiality, and procedural fairness. Deliberately concealing adverse records, coaching false evidence, inflating claims, or using delay tactically may breach professional duties and damage credibility. Project organisations should maintain approval controls for settlement authority and conflicts of interest.

Digital tools improve chronology building, document review, version control, and project records. Artificial intelligence may assist with searching, classification, translation, and identifying inconsistent dates. It must not be treated as an authoritative legal or factual decision-maker. Risks include fabricated citations, confidential-data leakage, biased classification, incomplete context, and inability to explain outputs. Human review, secure systems, audit trails, and disclosure of material reliance are essential.

Building information modelling and common data environments can reduce disputes by recording design versions, approvals, and responsibility interfaces. They do not eliminate disputes: poor access control, inconsistent naming, unauthorised model changes, and uncertain contractual status of digital information may create new ones. Contracts should identify the authoritative model, permitted uses, information ownership, retention, and responsibility for data quality.

13. Illustrative applied case: the Riverside Interchange

Background

The fictional Riverside Interchange project involves a public employer, a design-and-build contractor, and several specialist subcontractors. The contract requires early notice of delay and provides for adjudication followed by arbitration. The project has a dispute board that visits quarterly.

Problem

The employer issued revised fire-safety requirements after construction began. The contractor received the revised design late, resequenced work, and claimed 70 days of extension and additional preliminaries. The employer argued that the contractor should have anticipated the requirements and rejected the claim because the notice was submitted 18 days after the event rather than within the contractual 14-day period. Progress records also showed that the contractor’s steelwork subcontractor had suffered an independent 25-day delay.

Analysis

The project team first separated entitlement, causation, and quantum. The revised requirement appeared to be an employer-driven change, but the notice clause and any legal consequences of late notice required jurisdiction-specific analysis. The parties assembled the original and revised designs, transmittals, meeting minutes, programmes, site diaries, procurement records, and subcontractor correspondence.

A programme analysis indicated that the design change affected a critical fire-services sequence for 42 days. The independent steelwork delay affected a different path for 20 days, with a 10-day overlap. The analysis did not automatically convert all 70 claimed days into compensable delay; it tested logic, criticality, concurrency, and mitigation. The contractor also had to prove actual additional cost rather than relying solely on the claimed duration.

Approach and solution

The dispute board issued a non-binding recommendation that the parties negotiate around the evidence-supported period while preserving their rights on the legal effect of late notice. Senior representatives then mediated. They agreed to an interim 35-day extension, payment of verified additional site overhead for an agreed period, acceleration of selected fire-services activities, and referral of the unresolved notice issue to adjudication.

The adjudicator considered the notice, contract wording, causation evidence, and valuation. The decision was immediately effective under the contract, subject to later arbitration. The parties complied with the payment direction and later settled the remaining issue without arbitration.

Outcome and learning points

The result was less costly than a full hearing and preserved the project relationship. Key lessons were:

• early records allowed the critical-path effect to be tested;
• the board’s project familiarity supported a practical recommendation;
• negotiation addressed commercial interests beyond strict legal entitlement;
• partial settlement reduced the scope of formal determination; and
• a late notice should never be ignored: its effect depends on precise wording and applicable law.

Challenges and limitations

Dispute systems have inherent limitations. Early negotiation may reproduce unequal bargaining power. Mediation cannot guarantee settlement. Boards can be expensive and may lose independence if appointed or paid improperly. Adjudication may sacrifice depth for speed. Expert determination may be unsuitable for mixed legal and factual disputes. Arbitration may become as complex as litigation, while court proceedings may be slow and public.

There is also a systemic risk of fragmentation. Separate proceedings under connected contracts can produce inconsistent findings about the same delay or design. Alliance and integrated project-delivery models attempt to reduce this risk through shared incentives and collaborative governance, but they still require clear escalation and decision procedures.

Best-practice checklist

Before a dispute arises:

• verify governing law, forum, notices, limitation, and escalation clauses;
• maintain reliable contemporaneous records;
• operate change, design, payment, and programme controls;
• appoint independent board members or experts where appropriate; and
• train staff not to destroy, alter, or selectively preserve evidence.

When a dispute emerges:

• identify the event, entitlement, causation, and remedy;
• issue compliant notices without unnecessary argument;
• preserve documents and create a chronology;
• assess urgency, enforceability, relationship, and proportionality;
• obtain authority before making concessions;
• select the least adversarial effective mechanism; and
• obtain specialist legal and technical advice where complexity or value warrants it.

Chapter Summary

Dispute avoidance is a management discipline involving clear contracts, early warnings, competent administration, change control, accurate records, and collaborative conduct. When disagreement becomes a dispute, the parties can use a graduated range of mechanisms. Negotiation and mediation preserve flexibility; dispute boards provide project-informed intervention; statutory adjudication offers speed, especially for payment; expert determination suits focused technical issues; arbitration provides a private and potentially internationally enforceable adjudicative process; and litigation offers court powers, precedent, and remedies.

Selection must be strategic. Urgency, value, evidence, technical complexity, relationship, confidentiality, jurisdiction, enforceability, and cost all matter. Evidence must establish what happened, the applicable entitlement, causation, and the remedy. Cross-border projects require careful separation of governing law, seat, venue, and enforcement strategy. Ethical conduct, secure digital records, and responsible use of AI are essential to procedural fairness and professional credibility.

Key Terms

Dispute avoidance: Measures designed to prevent disagreements from becoming formal disputes.

Claim: An assertion that a party is entitled to a contractual or legal remedy.

Dispute: A crystallised disagreement requiring settlement or determination.

Negotiation: Direct discussion between parties seeking an agreed outcome.

Mediation: A facilitated, usually non-binding process in which a neutral helps parties settle.

Mediator: An independent person who manages communication without normally imposing a decision.

Dispute board: An independent project-appointed body that advises, recommends, or decides disputes.

Adjudication: A relatively rapid process producing a decision, often subject to later review.

Statutory adjudication: Adjudication created and regulated by legislation.

Expert determination: A specialist’s determination of a defined technical or valuation question.

Arbitration: A private adjudicative process based on party agreement.

Arbitral seat: The legal location governing the supervisory framework of an arbitration.

Litigation: Resolution through a public court process.

Jurisdiction: Legal authority of a court, tribunal, or decision-maker to hear a matter.

Natural justice: Procedural fairness, including impartiality and a fair opportunity to be heard.

Causation: The connection between an alleged breach or event and the claimed consequence.

Quantum: The amount or valuation of a claimed loss or entitlement.

Enforcement: Legal steps used to make a decision, judgment, or award effective.

Without prejudice: A protection that may restrict use of genuine settlement communications, subject to applicable law.

Review Questions

Short Answer Questions

1. Distinguish a claim from a dispute.
2. State two advantages and two limitations of mediation.
3. What is the difference between the seat and venue of arbitration?
4. Why are contemporaneous records important in construction disputes?
5. Identify three factors relevant to selecting a dispute-resolution mechanism.

Long Answer Questions

1. Explain how contract drafting and project administration can prevent disputes.
2. Compare statutory adjudication, arbitration, and litigation in relation to speed, cost, finality, and enforcement.
3. Discuss the role, benefits, and risks of dispute boards.
4. Explain how a party should prepare and prove a delay and prolongation claim.
5. Analyse the special jurisdictional and enforcement issues arising on cross-border construction projects.

Analytical / Application Questions

1. A contractor submits a payment claim 20 days after discovering an alleged valuation error. The contract requires notice within 14 days and provides for adjudication. Identify the procedural and substantive issues that should be investigated before referral.
2. An employer, contractor, and designer are bound by different dispute clauses concerning the same design change. Recommend a strategy to reduce inconsistent decisions and explain the risks of each available mechanism.
3. A project manager wants to use an AI system to search confidential records and draft a claim chronology. Evaluate the governance controls required before using the system and explain why human review remains necessary.

Multiple Choice Questions with Answers

Question 1

Which statement best distinguishes a claim from a dispute?

A. A claim is always decided by a court, while a dispute is never decided by a court.

B. A claim asserts an entitlement; a dispute generally arises when that entitlement is contested.

C. A claim can only concern payment, while a dispute can concern any issue.

D. A dispute exists before any party asserts an entitlement.

Correct Answer: B. A claim asserts an entitlement; a dispute generally arises when that entitlement is contested.

Question 2

What is the principal role of a mediator?

A. To impose a binding judgment on the parties

B. To act as an advocate for the weaker party

C. To facilitate communication and settlement without normally imposing a decision

D. To replace the project manager in administering the contract

Correct Answer: C. To facilitate communication and settlement without normally imposing a decision

Question 3

Which mechanism is generally most suitable for a narrow, specialist valuation question?

A. Expert determination

B. Jury trial

C. Unstructured negotiation only

D. Criminal prosecution

Correct Answer: A. Expert determination

Question 4

In arbitration, the legal significance of the seat is that it generally determines:

A. The physical location of every hearing

B. The nationality of every witness

C. The supervisory legal framework and courts

D. The contractor’s place of incorporation

Correct Answer: C. The supervisory legal framework and courts

Question 5

The policy commonly associated with statutory construction adjudication is:

A. Pay now, argue later

B. Never pay until final litigation ends

C. All disputes must be decided by a jury

D. Technical disputes cannot be referred

Correct Answer: A. Pay now, argue later

Question 6

Which item is part of proving causation in a delay claim?

A. Showing only that the project finished late

B. Showing how the event affected relevant programme logic and criticality

C. Showing that the claimant is dissatisfied

D. Showing that the contract has more than one schedule

Correct Answer: B. Showing how the event affected relevant programme logic and criticality

Question 7

Which process normally gives a court compulsory powers over parties and evidence?

A. Private negotiation

B. Mediation

C. Litigation

D. Informal board discussion

Correct Answer: C. Litigation

Question 8

Why can multi-contract construction projects create arbitration difficulties?

A. Arbitration never permits technical evidence

B. Connected parties may be bound by different clauses, causing fragmented proceedings

C. Arbitration automatically cancels all subcontractors’ rights

D. Arbitrators cannot hear payment disputes

Correct Answer: B. Connected parties may be bound by different clauses, causing fragmented proceedings

Question 9

Which practice best supports dispute avoidance?

A. Keeping records until a dispute is formally commenced

B. Using factual contemporaneous records and early-warning procedures

C. Avoiding all written instructions

D. Allowing only one party to approve design changes

Correct Answer: B. Using factual contemporaneous records and early-warning procedures

Question 10

What is a significant risk of using AI for dispute preparation?

A. It makes all evidence automatically admissible

B. It eliminates the need for legal analysis

C. It may leak confidential data or produce inaccurate outputs

D. It guarantees international enforcement

Correct Answer: C. It may leak confidential data or produce inaccurate outputs