Civil Law and UAE Architect Design Responsibility Cases

1. Introduction

Under UAE civil law, an architect or consulting engineer may have substantial legal responsibility for the design, structural safety, technical specifications, drawings, calculations, and, where contractually undertaken, supervision of construction.

The most important traditional UAE rules were contained in Articles 880–883 of Federal Law No. 5 of 1985 (Civil Transactions Law). From 1 June 2026, the new Federal Decree-Law No. 25 of 2025 (Civil Transactions Law) applies, with the decennial-liability provisions renumbered principally to Articles 821–824. The underlying distinction between design responsibility and supervision responsibility remains highly important.

A central principle is:

An architect who is responsible only for design is primarily responsible for defects arising from the design; an architect/engineer who also supervises execution can have broader responsibility for defects affecting the safety and stability of the building.

The UAE regime is particularly important because serious structural defects can trigger decennial liability, which is considerably stricter than ordinary contractual professional negligence.

2. Meaning of Architect Design Responsibility

Architect design responsibility refers to the legal obligation of an architect, engineer, or design consultant to ensure that the plans and technical design supplied for a construction project are professionally adequate and comply with the applicable contractual, technical, regulatory and safety requirements.

It may include:

1. architectural drawings;
2. structural design;
3. engineering calculations;
4. specifications;
5. fire-safety design;
6. electrical and mechanical design;
7. drainage and water systems;
8. foundation and soil-related design;
9. compliance with applicable building regulations;
10. coordination between different engineering disciplines;
11. identification of foreseeable design risks;
12. correction of defective designs;
13. design changes and revisions;
14. supervision, if expressly included in the consultant's mandate.

3. Current UAE Legal Framework

Because the UAE Civil Transactions Law changed on 1 June 2026, it is important to distinguish the old and new numbering.

The older cases discussed below were generally decided under the former Civil Transactions Law. They remain highly useful for understanding the judicial principles, but they should be treated as historical/doctrinal authorities when applying the new 2026 Code, rather than automatically assuming that every old statutory interpretation is unchanged.

4. Decennial Liability

The most important concept in architect design responsibility is decennial liability.

Traditionally, Article 880 imposed liability on the contractor and the architect/engineer involved in designing and supervising the construction for:

• total collapse;
• partial collapse; and
• defects threatening the stability or safety of the building.

The liability traditionally operated for ten years from delivery of the works.

The new Civil Transactions Law carries this concept into the new numbering, principally Article 821.

5. Why Decennial Liability Is Different

Ordinary professional negligence generally requires examination of:

Duty → breach → causation → damage.

Decennial liability is different because it is a special statutory construction guarantee.

The owner normally has to establish the relevant structural failure or qualifying defect and its connection to the statutory regime. The architect cannot simply escape responsibility by arguing:

“I exercised reasonable care.”

The statutory regime is therefore much stronger than an ordinary negligence claim.

6. Design-Only Architect Versus Supervising Architect

This distinction is fundamental.

A. Design-only architect

Where the architect's contractual role is limited to preparing the design, the architect's responsibility is principally for:

• defective drawings;
• defective calculations;
• inappropriate specifications;
• inadequate design;
• structural design errors;
• foreseeable design incompatibility;
• failure to meet applicable requirements.

The architect is generally not responsible merely because a contractor executed the design badly, where the architect had no supervisory responsibility.

B. Design-and-supervision architect

Where the architect also supervises construction, the responsibility can extend to defects arising during execution that affect the structural integrity or safety of the building.

Thus:

Design + supervision = broader responsibility

while

Design only = responsibility principally connected with defects in the design.

7. Case Law 1 — Federal Supreme Court, Civil and Commercial Appeal No. 416 of Judicial Year 27, 31 October 2006

This is one of the most important authorities concerning architect responsibility.

Principle

The Federal Supreme Court explained the distinction between the architect who designs and the architect who also controls/supervises construction.

The court recognized that the statutory rules concerning construction responsibility cover the architect and contractor, but where the architect's work is limited to preparing the design, the architect's liability is confined to defects resulting from that design.

Importance

This case establishes the basic allocation of responsibility:

Design responsibility follows the scope of the architect's professional mandate.

Therefore, an architect should not automatically be treated as responsible for every construction defect simply because the architect prepared the plans.

8. Case Law 2 — Dubai Court of Cassation, Civil Appeal No. 6 of 2004, 20 June 2004

This case is important for defining the scope of decennial construction liability.

Principle

The Dubai Court of Cassation emphasized that the statutory guarantee does not cover every defect discovered in a building.

The defect must involve:

• total or partial destruction; or
• a defect threatening the durability, stability or safety of the building.

Importance for architects

Suppose an architect's design contains:

• a minor aesthetic discrepancy;
• a small finishing problem; or
• a non-structural defect.

That does not automatically create decennial liability.

However, if the design causes a structural defect threatening the building's safety, the legal position is substantially different.

9. Case Law 3 — UAE Federal Supreme Court, Civil Appeal No. 267 of Judicial Year 17, 28 January 1996

This case concerned the statutory time limits applicable to construction defects.

Facts in principle

The owner discovered a defect within the ten-year period but did not commence legal proceedings within the applicable subsequent limitation period.

Decision

The Federal Supreme Court applied the former Article 883 limitation rule and held the claim time-barred.

Importance

The case demonstrates that two different temporal concepts must be distinguished:

1. the decennial liability period, and
2. the period within which the legal claim must be commenced after collapse or discovery of the defect.

For an architect, this means that a technically valid claim may nevertheless fail because of limitation.

10. Case Law 4 — UAE Federal Supreme Court, Civil Appeal No. 211 of Judicial Year 19, 14 February 1999

This is another important authority on construction-defect limitation.

Principle

The owner discovered a defect and communicated the problem to the contractor. Legal proceedings were commenced considerably later.

The Federal Supreme Court applied the limitation rule associated with the discovery of the defect and rejected the claim as time-barred.

Importance

The case illustrates that the owner cannot indefinitely postpone proceedings merely because the defect falls within the ten-year decennial period.

For architects and consultants, limitation is therefore a major defence.

11. Case Law 5 — Dubai Court of Cassation, Real Estate Judgment No. 539 of 2023

This is one of the most useful modern UAE decisions concerning design and supervision responsibility.

Background

A project owner alleged defects involving:

• fire-fighting systems;
• fire pumps;
• fire hydrant spacing;
• design and supervision;
• compliance with civil-defence requirements.

The consultant had undertaken infrastructure design and supervision functions.

Court's approach

The court relied heavily on expert evidence and examined whether there was actually:

• a design defect;
• a supervisory failure;
• a breach of the applicable regulations at the relevant time; and
• a structural defect sufficient to invoke decennial liability.

The court ultimately rejected the owner's claim because the evidence did not establish the alleged design/supervisory defects or the structural failure required for decennial liability.

Major principle

An architect or consultant is not automatically liable simply because a building later experiences a problem.

The claimant must establish the necessary technical and legal connection between:

design/supervision → defect → legally compensable damage.

The court also treated later regulatory requirements cautiously. A consultant should not automatically be judged against regulations introduced after the relevant design and construction.

Importance

This case is especially valuable in modern disputes because it demonstrates the importance of:

• expert evidence;
• contemporaneous regulations;
• contractual scope;
• causation;
• distinction between repair and upgrading;
• proof of actual structural defect.

12. Case Law 6 — Dubai Court of Cassation, Appeal No. 150 of 2007

This authority concerns the beneficiaries of construction-related liability.

Principle

The UAE courts recognized the contractual character of the architect/engineer's and contractor's responsibility toward the party to whom the construction work was contractually delivered.

Importance

It demonstrates that an architect's decennial responsibility cannot simply be treated as a universal guarantee owed to every person who happens to suffer loss connected with a building.

The court must examine:

• contractual relationships;
• statutory obligations;
• the identity of the claimant;
• the nature of the damage; and
• whether the particular statutory regime applies.

13. Case Law 7 — Dubai Court of Cassation, Appeal No. 77 of 2011

This case concerns defective construction work and the rights available to an employer when the work does not comply with contractual requirements.

Principle

The court emphasized that where completed works are defective and do not comply with contractual requirements, the owner may seek appropriate remedies, including requiring correction or, where legally justified, termination and completion through another contractor.

Relevance to architects

Although the case primarily concerns contractor obligations, it is important for determining the boundary between:

• design defects, and
• execution defects.

If the contractor failed to follow an adequate design, responsibility may fall principally upon the contractor.

If the contractor faithfully implemented a fundamentally defective design, responsibility may instead point toward the design consultant, depending upon contractual scope and the applicable statutory regime.

14. Case Law 8 — DIFC Court of First Instance, BAM Higgs & Hill LLC v Affan Innovative Structures LLC & Amer Affan, CFI-106-2021

This is a DIFC construction case and therefore must be distinguished from ordinary onshore UAE Civil Code jurisprudence.

The case nevertheless provides useful construction-law reasoning concerning contractual performance, defective works and allocation of responsibility.

Importance

The decision illustrates the importance of determining:

• what each professional was contractually required to do;
• whether the work complied with contractual specifications;
• whether defects were caused by design or workmanship; and
• which party assumed the relevant risk.

It is useful as persuasive DIFC construction authority, rather than as a direct precedent under the onshore UAE Civil Transactions Law.

15. Case Law 9 — Architeriors Interior Design LLC v Emirates National Investment Co LLC, DIFC TCD 001/2024

This is another useful DIFC Technology and Construction Division authority.

The dispute concerned construction works, consultant involvement, specifications, defects and remedial obligations.

Importance

The case demonstrates that courts examine the actual contractual allocation of responsibility rather than assuming that every defect belongs to the architect, contractor or employer.

For an architect, the relevant questions include:

1. Who prepared the design?
2. Who approved it?
3. Who was responsible for coordination?
4. Who supervised construction?
5. Who selected materials?
6. Who was responsible for correcting defects?
7. What did the contract say about design risk?

This contractual allocation is extremely important in modern UAE projects.

16. Case Law 10 — Dubai Court of Cassation, Case No. 290 of 2021

This case arose from a construction dispute involving a developer, contractor and consultant.

The consultant had performed design and supervisory functions, while the contractor was separately engaged.

Importance

The case is particularly useful because it illustrates the complications created by multiple contracts.

An architect may have:

• one contract with the developer;
• another relationship with the contractor;
• a separate consultant agreement;
• an arbitration clause;
• statutory construction responsibilities.

Therefore, identifying the architect's liability requires examining the entire contractual structure.

17. The Role of Expert Evidence

Architectural and engineering disputes are heavily dependent upon technical evidence.

A court normally cannot determine questions such as:

• whether a foundation was properly designed;
• whether structural calculations were adequate;
• whether a fire system was properly designed;
• whether a specification was technically defective;
• whether a defect resulted from design or workmanship;

without appropriate technical evidence.

A court-appointed expert or expert panel may therefore become central to the dispute.

18. Architect's Duty of Professional Skill

Apart from special decennial liability, professional responsibility can arise from the general civil-law principle that a professional must exercise the level of skill and care ordinarily expected from a person practicing that profession.

For an architect, this may include:

• proper technical investigation;
• adequate calculations;
• reasonable design coordination;
• appropriate material selection;
• compliance with applicable standards;
• consideration of foreseeable risks;
• accurate drawings;
• proper revision control;
• professional warnings.

The exact contractual standard remains important.

19. Design Error as a Breach

Examples of potentially actionable design errors include:

Structural

• insufficient load-bearing capacity;
• inadequate foundation design;
• inappropriate structural calculations;
• failure to account for foreseeable loads.

Fire safety

• inadequate fire exits;
• insufficient fire protection;
• improper fire compartmentation;
• defective fire-system design.

Mechanical/electrical

• inadequate capacity;
• incompatible systems;
• unsafe electrical specifications;
• inadequate ventilation.

Water and drainage

• inadequate drainage design;
• improper hydraulic calculations;
• defective waterproofing specifications.

The legal consequence depends upon whether the defect merely causes inconvenience or threatens the stability/safety of the building.

20. Design Defect Versus Construction Defect

This distinction can be represented as follows:

An architect who is design-only is generally much more exposed to the first column than the second.

21. What If the Contractor Notices a Design Error?

The contractor may have its own professional obligations.

Suppose an architect provides a structural drawing that contains an obvious technical error.

The contractor notices the error but proceeds without warning the employer.

The court may need to consider:

• contractual obligations;
• professional standards;
• whether the contractor had design responsibility;
• whether the error was obvious;
• causation;
• contribution to the damage.

Therefore, design responsibility does not necessarily mean that the contractor can ignore obvious technical problems.

22. Architect's Liability for Regulatory Compliance

An architect should normally design in accordance with the applicable requirements existing when the design obligation is performed.

Relevant requirements may include:

• building regulations;
• municipality requirements;
• fire and civil-defence requirements;
• planning restrictions;
• health and safety requirements;
• environmental requirements;
• technical codes incorporated into the project.

However, the 2023 Dubai Court of Cassation Judgment No. 539 of 2023 demonstrates why the date of the applicable regulation matters.

A later regulatory change cannot automatically establish that an earlier design was defective.

23. Later Regulatory Changes

Consider:

Design approved in 2010 → construction completed in 2012 → regulation changed in 2017 → owner demands redesign in 2026.

The architect should not automatically be liable merely because the old design does not comply with the 2017 standard.

The court will consider:

1. what regulations applied when the design was prepared;
2. whether the architect had a contractual obligation to update the design;
3. whether the defect existed independently of the later regulation;
4. whether the later requirement is retrospective;
5. whether the claimed cost is repair or merely upgrading.

24. Design Changes During Construction

Architects may also become exposed to liability through design changes.

For example:

Original structural design → architect approves change → additional load imposed → structural cracking occurs.

The court may examine:

• who proposed the change;
• who approved it;
• whether calculations were performed;
• whether the architect warned the owner;
• whether the contractor followed the revised design;
• whether the change caused the defect.

Documentation is therefore extremely important.

25. Architect's Supervision Responsibility

Where the architect is appointed as supervising consultant, responsibility becomes broader.

Supervision may include:

• inspecting construction;
• checking conformity with drawings;
• certifying completed work;
• identifying defective workmanship;
• monitoring testing;
• issuing instructions;
• approving variations;
• reporting serious defects.

However, supervision does not necessarily mean continuous physical presence at every moment of construction.

The contractual scope must be examined.

26. Certification Does Not Automatically Eliminate Liability

An architect who certifies work as completed may face additional exposure if the certification was:

• materially inaccurate;
• issued without required inspection;
• inconsistent with known defects;
• contrary to contractual duties.

But certification alone does not automatically prove negligence.

The claimant still needs to establish the legal and factual connection between the consultant's conduct and the damage.

27. Decennial Liability and Minor Defects

Not every defect triggers decennial liability.

Examples potentially outside decennial liability

• paint defects;
• minor tiles;
• cosmetic finishes;
• ordinary wear;
• minor plumbing inconvenience;
• aesthetic imperfections.

Potentially within decennial liability

• structural collapse;
• dangerous foundation failure;
• serious structural cracking;
• defects threatening structural stability;
• major defects threatening building safety.

The courts have repeatedly emphasized this distinction.

28. Strict Liability Does Not Mean Unlimited Liability

The architect may be subject to strict statutory liability in qualifying cases, but that does not mean that every loss connected with a building automatically becomes recoverable.

There must still be:

• a qualifying statutory event;
• a relevant building/construction relationship;
• damage;
• proper claimant status;
• applicable statutory period;
• compliance with procedural requirements.

29. Contractual Liability Outside Decennial Liability

An architect may also face ordinary contractual liability.

For example, an architectural agreement may require the consultant to:

• complete drawings by a particular date;
• obtain approvals;
• coordinate consultants;
• provide BIM models;
• revise drawings;
• supervise construction;
• issue certificates.

Failure to perform such obligations can create contractual damages even where there is no structural collapse.

Thus:

Decennial liability ≠ the entire universe of architect liability.

30. Tortious Liability

Civil liability can also arise through general UAE civil-liability principles.

A claimant may potentially argue that the architect's conduct caused damage through:

• professional negligence;
• wrongful conduct;
• failure to exercise professional care;
• causation of property damage.

The precise interaction between contractual and tortious claims depends on the parties, the cause of action and the applicable provisions of the current Civil Transactions Law.

31. Causation

Causation is often the most difficult issue.

Suppose a building develops cracks.

Possible causes include:

1. defective architectural design;
2. defective structural calculations;
3. poor construction;
4. poor-quality materials;
5. soil movement;
6. groundwater;
7. owner's alterations;
8. inadequate maintenance;
9. extraordinary external events.

The court therefore cannot simply conclude:

“There is a defect, therefore the architect is liable.”

The technical evidence must connect the defect to the architect's responsibility.

32. Multiple Causes

Construction defects frequently have multiple causes.

For example:

Design error + poor workmanship + defective materials = structural damage.

The court may then determine the respective responsibilities of:

• architect;
• structural engineer;
• contractor;
• subcontractor;
• supplier;
• owner.

This is why expert evidence and contractual documents are critical.

33. Employer's Consent

Under the traditional decennial regime, the employer's approval of defective construction did not necessarily eliminate statutory liability.

This reflects the protective nature of decennial liability.

Therefore:

“The owner approved the design”

is not necessarily a complete defence to a qualifying statutory claim.

The precise application under the 2026 Civil Transactions Law must, however, be assessed under the new statutory wording.

34. Contractual Limitation of Architect Liability

Under the former Article 882 regime, agreements attempting to exclude or limit decennial liability were ineffective.

The new Civil Transactions Law retains the special statutory regime in renumbered provisions.

Therefore, architects and employers should distinguish between:

Ordinary contractual liability

Potentially subject to contractual allocation/limitations, subject to mandatory law.

Statutory decennial liability

Subject to mandatory statutory restrictions.

A contractual cap cannot simply be assumed to eliminate a mandatory statutory responsibility.

35. Limitation and Time Bars

Historically under Article 883:

• the decennial period operated from delivery; and
• a claim concerning collapse or discovery of a qualifying defect had to be brought within the statutory period.

The cases Federal Supreme Court Civil Appeals Nos. 267/17 and 211/19 demonstrate the importance of these time limits.

Under the 2026 Civil Transactions Law, lawyers must check the new Articles 821–824 rather than mechanically applying the former numbering.

36. New Civil Transactions Law and Architect Responsibility

From 1 June 2026, the relevant legal analysis should begin with the new Civil Transactions Law.

The important conceptual structure remains:

Architect's contractual role

↓

Design responsibility

↓

Supervision responsibility, if undertaken

↓

Structural/safety defect

↓

Decennial liability where statutory conditions are satisfied

↓

Compensation and other appropriate remedies

The major practical change is the renumbering and updated statutory framework, not the disappearance of architect/engineer responsibility.

37. Burden of Proof

In an ordinary design-defect dispute, the claimant generally needs to establish the factual foundation of the claim.

Important evidence includes:

• original drawings;
• revised drawings;
• structural calculations;
• BIM records;
• specifications;
• consultant agreement;
• emails;
• site instructions;
• inspection reports;
• approval certificates;
• municipality approvals;
• Civil Defence approvals;
• expert reports;
• photographs;
• testing records.

38. Importance of the Consultant's Contract

The first document a court should examine is often the consultancy agreement.

It may answer:

• Was the architect responsible only for design?
• Was supervision included?
• Was contract administration included?
• Was approval of shop drawings included?
• Was site inspection required?
• Was fire-system design included?
• Was structural engineering separately appointed?
• Was the architect responsible for obtaining authority approvals?

The scope of appointment can therefore determine the boundary of responsibility.

39. Practical Example

Assume an architect designs a five-storey building.

The architect's calculations contain a fundamental structural error.

The contractor follows the plans exactly.

After completion, major structural cracking appears and experts conclude that the design cannot safely support the building.

Likely legal analysis

The architect cannot simply say:

“The contractor built exactly what I designed.”

If the architect was responsible for the design, the defect may directly arise from the architect's professional work.

If the defect threatens structural safety, the decennial regime may become relevant.

40. Second Example — Contractor Deviates From Design

Suppose the architect provides an adequate design, but the contractor:

• substitutes cheaper steel;
• ignores structural drawings;
• changes foundation depth;
• uses inferior concrete.

The resulting structural defect is caused by construction rather than design.

A design-only architect would have a substantially stronger defence, provided the architect had no contractual supervisory responsibility and did not approve the deviation.

41. Third Example — Architect Supervises

Suppose the architect both designs and supervises.

The contractor uses inadequate materials.

The architect's site engineer repeatedly observes the problem but fails to issue an appropriate warning or instruction.

The claimant may argue that the architect's supervisory obligation was breached.

The court would then examine the contractual scope and technical evidence.

42. Important Lessons From the Cases

43. Key Legal Tests for Architect Liability

A UAE court dealing with an architect design claim will generally need to ask:

Test 1 — What was the architect hired to do?

Design only or design plus supervision?

Test 2 — Was there a defect?

Is there a technically established defect?

Test 3 — What caused the defect?

Design, workmanship, materials, soil, maintenance or another cause?

Test 4 — Does it threaten structural safety?

If yes, decennial liability may become relevant.

Test 5 — Was the defect within the architect's contractual responsibility?

This is essential for design-only professionals.

Test 6 — Is the claim timely?

The statutory limitation regime must be examined.

Test 7 — What damage actually resulted?

Repair costs, consequential losses and upgrading costs should not automatically be treated as identical.

44. Architect's Defences

An architect may rely upon several defences depending on the facts:

1. No design defect existed.
2. The defect resulted from contractor workmanship.
3. The contractor departed from approved drawings.
4. The architect had no supervisory obligation.
5. The defect resulted from owner alterations.
6. The damage resulted from inadequate maintenance.
7. The alleged requirement arose after the design was completed.
8. The claimant cannot establish causation.
9. The claim is time-barred.
10. The claimed expenditure represents an upgrade rather than repair.
11. The alleged defect does not threaten structural stability or safety.
12. The architect's contractual scope did not include the relevant work.

45. Importance of the 2023 Dubai Case

Dubai Court of Cassation, Real Estate Appeal No. 539/2023 deserves particular attention for modern practice.

It demonstrates that an architect/consultant cannot be held responsible merely because:

• a system later required modification;
• a new regulatory standard appeared;
• the owner incurred upgrade costs.

There must be evidence that the consultant's actual design or supervision was defective under the applicable requirements and contractual scope.

46. Architect Design Responsibility and Insurance

Architects and engineering consultants should consider professional indemnity insurance because design claims can involve:

• large repair costs;
• structural damage;
• consequential losses;
• expert fees;
• litigation/arbitration costs;
• statutory decennial exposure.

Insurance does not necessarily eliminate statutory responsibility; it is primarily a mechanism for managing financial risk.

47. Arbitration and Architect Liability

Architectural contracts frequently contain arbitration clauses.

A dispute may therefore involve:

• developer vs architect;
• developer vs contractor;
• architect vs contractor;
• contractor vs subcontractor.

The existence of different dispute-resolution clauses can create jurisdictional complications, particularly where the contractor and consultant have separate contracts.

Dubai Court of Cassation Case No. 290/2021 illustrates this type of multi-contract problem.

48. Role of Court Experts

In serious design disputes, the court may appoint technical experts to determine:

• whether the design was technically correct;
• whether the design complied with applicable regulations;
• whether the contractor followed the design;
• whether construction deviated from the drawings;
• the cause of structural failure;
• cost of repair;
• whether proposed works are repair or upgrade.

The court remains responsible for the ultimate legal conclusion.

49. Design Responsibility in Modern Projects

Modern UAE projects create additional issues involving:

• BIM;
• digital drawings;
• AI-assisted design;
• parametric architecture;
• automated structural calculations;
• imported designs;
• foreign engineering consultants;
• specialist subcontractors;
• design-and-build contracts.

The use of technology does not automatically transfer legal responsibility to the software.

The professional who undertakes the design must carefully examine the output and comply with the applicable professional and contractual obligations.

50. Overall Legal Position

The UAE approach can be summarized as:

An architect is responsible for the design work undertaken within the architect's professional and contractual scope. Where the architect also supervises construction, responsibility can extend beyond pure design defects. For serious structural defects or defects threatening safety and stability, the UAE's special decennial-liability regime can impose particularly strong statutory responsibility on the architect/engineer and contractor.

The most important cases are Federal Supreme Court Appeal No. 416/27 (2006) and Dubai Court of Cassation Real Estate Judgment No. 539/2023, because together they illustrate two complementary principles:

1. the scope of architect responsibility depends on whether the role is design-only or includes supervision; and
2. a claimant must still establish the technical and legal basis for liability rather than merely pointing to the existence of a defect.

Important 2026 qualification

Because the new UAE Civil Transactions Law became effective on 1 June 2026, the older cases above should be cited as pre-2026 judicial authorities interpreting the former Civil Transactions Law. For a dispute governed by the new Code, the corresponding Articles 821–824 should be checked directly, together with the transitional provisions and the precise date and nature of the construction contract, delivery and defect.