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AI Failure Dictionary

Data & Problem Definition Failures

Data & Problem Definition Failures terms and explanations from the AI Failure Dictionary.

71 terms in this chapter
01

Problem Misframing

Definition

The team solves the wrong problem with AI, such as building a prediction model when the real issue is a broken workflow.

Solution

Clarify the business goal, user pain point, decision process, and success criteria before modeling.

02

Objective Misalignment

Definition

The model optimizes for something different from what the business actually needs.

Solution

Align model objectives with measurable product, user, safety, and business outcomes.

03

Metric Misalignment

Definition

A metric improves, but real user experience or business value does not improve.

Solution

Choose metrics that reflect user value, quality, safety, and business impact.

04

Success Criteria Ambiguity

Definition

The team does not clearly define what ``good enough'' means.

Solution

Set acceptance thresholds, quality gates, and launch criteria before training or deployment.

05

Use Case Overreach

Definition

AI is used for a task where rules, workflow automation, or human review would be better.

Solution

Validate whether AI is truly needed and compare it against simpler non-AI solutions.

06

Stakeholder Misalignment

Definition

Product, data, engineering, legal, security, and leadership teams disagree on the goal.

Solution

Document ownership, requirements, risks, responsibilities, and approval flow.

07

Requirement Drift

Definition

Business requirements change, but the model or pipeline is not updated.

Solution

Schedule regular requirement reviews and connect them to model and pipeline update cycles.

08

Risk Misclassification

Definition

A high-risk AI use case is treated as low-risk, or a low-risk use case is over-controlled.

Solution

Apply risk assessments early and classify use cases by impact, safety, privacy, and compliance needs.

09

Automation Bias

Definition

Humans trust AI output too much just because it came from a model.

Solution

Show confidence, evidence, warnings, uncertainty, and human review options.

10

Human-in-the-Loop Failure

Definition

The system needs human review, but the review process is missing, weak, or ignored.

Solution

Add escalation rules, reviewer queues, override mechanisms, and clear decision ownership.

11

Feedback Design Failure

Definition

The system does not collect useful feedback for improvement.

Solution

Design feedback buttons, correction workflows, review notes, and feedback-to-evaluation loops.

12

Decision Boundary Confusion

Definition

The system does not define when AI should decide, recommend, refuse, or escalate.

Solution

Create clear decision boundaries, fallback paths, and human approval rules.

13

Data Unavailability

Definition

The needed data does not exist or cannot be accessed.

Solution

Identify alternative sources, collect new data, redesign the use case, or narrow the scope.

14

Data Access Failure

Definition

Permissions, APIs, governance rules, or system issues block access to data.

Solution

Create approved access paths, data-sharing agreements, and secure permission workflows.

15

Sampling Bias

Definition

The collected data does not represent the real-world population.

Solution

Improve the sampling strategy and add missing groups, regions, languages, or scenarios.

16

Selection Bias

Definition

Some examples are more likely to appear in the dataset than others.

Solution

Audit how data was collected and rebalance or supplement the dataset.

17

Survivorship Bias

Definition

The dataset only includes successful or surviving examples and hides failures.

Solution

Intentionally collect failed, rejected, abandoned, or negative examples.

18

Historical Bias

Definition

Past human or system bias is embedded in the collected data.

Solution

Audit labels, decisions, and outcomes across sensitive or important user groups.

19

Measurement Bias

Definition

Logs, sensors, surveys, or tracking tools collect inaccurate data.

Solution

Validate measurement tools, fix instrumentation, and compare against trusted references.

20

Proxy Data Failure

Definition

The team uses an indirect variable that poorly represents the real target.

Solution

Choose labels and features that more directly represent the desired outcome.

21

Low Data Coverage

Definition

Important users, edge cases, languages, regions, or scenarios are missing.

Solution

Expand the dataset and add coverage tests for critical scenarios.

23

PII Collection Failure

Definition

Personally identifiable information is collected when it is not needed.

Solution

Minimize collection and mask, tokenize, or remove sensitive fields.

24

Data Ownership Ambiguity

Definition

No team clearly owns the data source or its quality.

Solution

Assign data owners, quality responsibilities, and escalation paths.

25

Event Logging Gap

Definition

Important user or system events are not logged.

Solution

Define required events and telemetry before building the model or analytics pipeline.

26

Logging Inconsistency

Definition

Different systems log the same event in different formats.

Solution

Standardize event schemas, names, timestamps, and required fields.

27

Data Source Instability

Definition

A source system changes, breaks, or becomes unreliable.

Solution

Use data contracts, source monitoring, fallback sources, and versioned interfaces.

28

Synthetic Data Mismatch

Definition

Synthetic data does not behave like real-world data.

Solution

Validate synthetic data against real samples and limit it to scenarios where it improves coverage.

29

Third-Party Data Risk

Definition

External data is incomplete, biased, stale, or legally risky.

Solution

Validate vendor quality, licensing, update frequency, and compliance requirements.

30

Missing Values

Definition

Important fields are empty, null, or unavailable.

Solution

Use imputation, default handling, validation rules, or better collection processes.

31

Duplicate Records

Definition

The same entity or event appears multiple times.

Solution

Apply deduplication rules, unique identifiers, and record-linking checks.

32

Data Corruption

Definition

Data becomes malformed, damaged, unreadable, or incorrectly encoded.

Solution

Add validation checks and recover from clean backups or trusted raw sources.

33

Data Inconsistency

Definition

The same concept is recorded differently across systems.

Solution

Use standard schemas, normalization, and data contracts.

34

Schema Mismatch

Definition

Incoming data does not match the expected structure or type.

Solution

Use schema validation and producer-consumer contract testing.

35

Schema Drift

Definition

The structure of the data changes unexpectedly over time.

Solution

Monitor schema changes and use versioned schemas with compatibility checks.

36

Invalid Values

Definition

Data contains impossible, out-of-range, or wrongly formatted values.

Solution

Reject, correct, or quarantine invalid records with validation rules.

37

Outliers

Definition

Extreme values distort training, evaluation, or monitoring.

Solution

Investigate root causes and apply clipping, transformation, robust models, or special handling.

38

Label Noise

Definition

Training labels are wrong, inconsistent, or unreliable.

Solution

Improve labeling guidelines, reviewer training, consensus labeling, and label audits.

39

Bad Labels

Definition

The target values are incorrect because of human error, automation error, or unclear definitions.

Solution

Relabel samples, review edge cases, and measure inter-annotator agreement.

40

Incomplete Records

Definition

Records are missing required fields.

Solution

Enforce completeness checks before publishing data downstream.

41

Stale Data

Definition

The data is outdated and no longer reflects reality.

Solution

Refresh data more often and monitor freshness.

42

Data Leakage

Definition

Information that should not be available leaks into training or evaluation.

Solution

Review features, splits, joins, time boundaries, and target availability carefully.

43

Target Leakage

Definition

A feature accidentally contains information about the label.

Solution

Remove features that would not be available at prediction time.

44

Temporal Leakage

Definition

Future information is used to predict the past or present.

Solution

Use time-aware splits and enforce prediction-time availability rules.

45

Join Error

Definition

Tables are joined incorrectly, creating wrong relationships or duplicated rows.

Solution

Validate join keys, row counts, cardinality, and sample outputs after joins.

46

Entity Resolution Failure

Definition

Records belonging to the same person, product, company, or object are not matched correctly.

Solution

Use stronger identity matching, fuzzy matching, and manual review samples.

47

Unit Mismatch

Definition

Values use inconsistent units, such as dollars versus cents or meters versus feet.

Solution

Standardize units and add unit validation tests.

48

Time Zone Error

Definition

Events are processed or compared using incorrect time zones.

Solution

Store timestamps in UTC and convert only at the presentation layer.

49

Data Granularity Mismatch

Definition

Data from different levels is mixed incorrectly, such as user-level and transaction-level data.

Solution

Align data to the correct grain before aggregation, joining, or modeling.

50

Class Imbalance

Definition

Some classes appear much more often than others.

Solution

Use resampling, class weights, threshold tuning, better metrics, or more minority-class data.

51

Data Sparsity

Definition

There are too few useful examples for the model to learn reliable patterns.

Solution

Collect more data, simplify the model, use transfer learning, or aggregate related signals.

52

Dataset Bias

Definition

The dataset overrepresents or underrepresents certain groups, cases, or outcomes.

Solution

Run dataset audits, rebalance data, and evaluate performance across subgroups.

53

Data Poisoning

Definition

Bad or malicious data is inserted into training, retrieval, or evaluation data.

Solution

Validate sources, detect anomalies, review suspicious data, and protect ingestion pipelines.

54

Data Validation Failure

Definition

Bad data passes through because validation rules are missing or weak.

Solution

Add automated checks for schema, range, freshness, volume, uniqueness, and business rules.

55

Weak Feature Signal

Definition

Features do not contain enough useful information for prediction.

Solution

Create stronger domain-informed features or collect better data.

56

Irrelevant Features

Definition

Features add noise without improving model performance.

Solution

Use feature selection, importance analysis, and ablation testing.

57

Feature Leakage

Definition

A feature exposes information unavailable at prediction time.

Solution

Remove future-looking, target-derived, or post-outcome features.

58

Feature Drift

Definition

A feature's distribution or meaning changes over time.

Solution

Monitor feature statistics and retrain or update features when needed.

59

Feature Skew

Definition

Training features are computed differently from production features.

Solution

Share feature logic using a feature store or common production library.

60

Feature Store Staleness

Definition

Stored features are outdated.

Solution

Add freshness checks, scheduled updates, and stale-feature alerts.

61

Feature Duplication

Definition

Multiple features represent the same signal and distort learning.

Solution

Remove redundant features and check correlation or mutual information.

62

Poor Encoding

Definition

Categorical, text, or time features are encoded in a way that loses meaning.

Solution

Use better encoding strategies such as embeddings, one-hot encoding, target encoding, or cyclical time features.

63

Scaling Error

Definition

Numerical features are normalized or standardized incorrectly.

Solution

Fit scalers only on training data and reuse the same scaler in production.

64

Missing Feature Handling Failure

Definition

The model cannot handle null or unavailable features properly.

Solution

Use imputation, default values, missingness indicators, or model-native missing handling.

65

High Cardinality Failure

Definition

A feature has too many unique values, making learning unstable.

Solution

Use embeddings, hashing, grouping, frequency thresholds, or domain grouping.

66

Spurious Feature

Definition

The model relies on a feature that correlates with the label but does not generalize.

Solution

Use stress tests, causal review, subgroup checks, and out-of-distribution evaluation.

67

Time Window Error

Definition

Aggregated features use the wrong time range.

Solution

Define lookback windows clearly and prevent future leakage.

68

Feature Explosion

Definition

Too many features increase complexity, cost, and overfitting risk.

Solution

Use feature pruning, regularization, and ablation analysis.

69

Feature Versioning Failure

Definition

Teams cannot track which feature version was used by a model.

Solution

Version feature definitions and connect them to experiment tracking.

70

Feature Reuse Risk

Definition

A feature built for one use case is reused where it behaves badly.

Solution

Validate reused features for the new use case before adoption.

71

Feature Availability Failure

Definition

A feature exists during training but is unavailable during inference.

Solution

Check online availability and prediction-time constraints before training.

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