Definitions & Scope

This page establishes the foundation for the CDMA (Criteria-based Disease Matrix Analysis) framework—its purpose, scope, methodology, and key conventions for interpretation.

Project Purpose

The U.S. swine industry faces an evolving set of infectious disease threats, from transboundary pathogens that may enter through global trade to endemic diseases that could mutate or spread in new ways. Effective allocation of research funding, diagnostic development, and emergency preparedness resources requires a systematic approach to disease prioritization.

This framework applies Multi-Criteria Decision Analysis (MCDA) to pig disease prioritization, providing:

  • Transparent evaluation across standardized criteria
  • Stakeholder-informed weighting through structured expert elicitation
  • Evidence-based scoring with documented justifications
  • Reproducible methods that can be updated as new diseases emerge or knowledge evolves

The goal is a defensible, science-based ranking of swine pathogens to guide investment decisions by the Swine Health Information Center (SHIC) and the broader industry.

Geographic and Population Scope

Geographic focus: United States pig production systems

Population: Commercial domestic pigs in the United States. The framework addresses production systems where disease impacts are economically significant and where coordinated intervention is feasible. While principles may apply to backyard or hobby operations, the criteria and level definitions are calibrated to commercial production contexts.

Diseases included: The framework evaluates any pig disease relevant to US production, including:

  • Endemic diseases currently circulating in US swine populations
  • Foreign animal diseases not currently present but posing introduction risk
  • Emerging diseases recently recognized or with novel characteristics
  • Zoonotic diseases transmissible to humans, whether or not they cause significant pig disease

Diseases are assessed based on their potential impact if present in US production systems, not solely on current prevalence. This allows comparison of established endemic diseases alongside foreign animal diseases that have not yet arrived.

MCDA Methodology

The PAPRIKA Approach

This framework uses the PAPRIKA method (Potentially All Pairwise RanKings of all possible Alternatives), implemented through the 1000minds software platform. PAPRIKA works by presenting experts with repeated pairwise comparisons between hypothetical disease profiles that differ on only two criteria at a time. For each pair, the expert selects which disease they consider the higher priority for research investment.

Through this series of simple trade-off decisions, the algorithm derives the implicit weights each expert assigns to each criterion. These weights are then applied to disease scores to generate ranked priority lists.

Why PAPRIKA?

The method offers several advantages over simpler scoring approaches:

  • Avoids arbitrary weighting: Rather than asking experts to directly assign percentage weights to criteria, PAPRIKA derives weights from revealed preferences through concrete trade-off decisions
  • Handles cognitive complexity: Experts make simple binary choices rather than simultaneously weighing multiple criteria
  • Ensures internal consistency: The algorithm detects and flags logically inconsistent responses
  • Enables aggregation: Individual expert weights can be combined to reflect collective stakeholder priorities
  • Supports sensitivity analysis: Rankings can be tested against alternative weighting scenarios

Stakeholder Engagement

The PAPRIKA elicitation involves representatives from diverse perspectives:

  • Swine veterinarians and production specialists
  • Diagnostic laboratory directors
  • Academic researchers
  • Government animal health officials
  • Industry organization representatives

This breadth ensures that criteria weights reflect the priorities of those who will use the results for decision-making.

Disease Briefs

Each disease in this framework has an associated disease brief—a standardized document summarizing available evidence and assigning levels across all 11 evaluation criteria.

Purpose of Disease Briefs

Disease briefs serve multiple functions:

  • Reference material for experts during PAPRIKA scoring sessions
  • Documentation of the evidence basis for each level assignment
  • Transparency enabling scrutiny and future revision as knowledge evolves
  • Consistency ensuring all diseases are evaluated against the same criteria

Structure

Each disease brief includes:

  1. LEVELS line: A semicolon-separated list of the 11 assigned levels, enabling automated parsing
  2. Overview: A summary paragraph describing the disease, its causative agent, and relevance to US pig production
  3. Criterion sections: For each of the 11 criteria, the assigned level and a justification paragraph explaining the evidence basis

Interpreting Level Assignments

All criteria are framed with levels progressing from least concern to greatest concern. This ensures:

  • Consistent interpretation across all criteria
  • Intuitive comparisons in PAPRIKA trade-off questions
  • Clear prioritization logic (diseases with greater concern rank higher)

When reviewing a disease brief, higher-ranked levels indicate greater concern or impact within that criterion.

Evidence Standards

Disease assessments are based on:

  • Peer-reviewed scientific literature (primary source)
  • National and international surveillance data
  • Diagnostic laboratory findings
  • Expert consensus when empirical data are limited
  • Field observations from practicing veterinarians

Assessments should clearly distinguish:

  • Established facts supported by multiple independent sources
  • Provisional conclusions based on limited data
  • Theoretical risks extrapolated from related pathogens or laboratory findings

Speculative or theoretical risks must be explicitly identified as such in disease briefs. The goal is honest characterization of current knowledge, including its limitations.

Handling Uncertainty

Uncertainty is inherent in disease assessment, particularly for emerging or poorly characterized pathogens.

When evidence is limited or conflicting:

  1. State the uncertainty explicitly in the disease brief justification
  2. Document the basis for the level assignment despite uncertainty
  3. Consider the precautionary principle for high-consequence unknowns
  4. Flag diseases for reassessment when new data become available

For emerging diseases: Criterion 11 (Eradication Feasibility) includes a dedicated level—"Feasibility of eradication not known"—for diseases where insufficient field experience precludes confident assessment.

Pending assessments: Diseases identified in source materials but lacking sufficient information for complete evaluation are tracked in a separate pending diseases file, with documentation of what is known and what information gaps prevent full assessment.

Framework Maintenance

This framework is designed to be living documentation that evolves with scientific knowledge and stakeholder priorities.

Revision triggers:

  • New diseases emerge requiring assessment
  • Significant new evidence changes understanding of existing diseases
  • Stakeholder feedback identifies unclear or problematic criteria definitions
  • PAPRIKA elicitation reveals criteria that fail to differentiate diseases meaningfully

Version control: All changes to criteria definitions, level descriptions, or disease assessments are tracked with revision dates and rationale.

Relationship to Other Pages

  • Criteria & Levels: Detailed definitions of each criterion and its levels, including guidance on how to distinguish between adjacent levels
  • Disease Briefs: Individual assessments accessible through the Diseases navigation menu
  • Home: Overview of the framework and quick links to disease briefs