Methodology and Assumptions

This page documents the shared analytical assumptions and interpretive rules applied across all research published on Odyssey Discoveries.

These assumptions are defined once, centrally, to ensure consistency, comparability, and transparency across datasets, articles, and analytical tools. Individual studies may add context-specific notes, but unless explicitly stated otherwise, the rules below apply.

Scope of Application

Unless explicitly stated otherwise, all analysis published on this site:

  • Uses city-proper (municipal) boundaries, not metropolitan or regional aggregates

  • Applies per-capita normalization where population context is relevant

  • Treats certification labels as signals, not performance scores

These shared assumptions allow results to be compared meaningfully across cities, routes, and systems.

City Boundary Definitions

Cities are defined using official municipal (city-proper) boundaries, rather than wider metropolitan or commuter regions.

This approach:

  • Avoids inflation from suburban or exurban spillover

  • Enables fair per-capita comparison between cities of different sizes

  • Aligns with the population baselines available from official statistical sources

Where metropolitan or regional definitions are required, this is explicitly noted in the relevant dataset or article.

Population Baselines

Population figures are sourced from:

  • The most recent national census or official municipal register available

  • City-proper population counts only, not metro-area estimates

Per-capita metrics are used to contextualize scale, not to rank cities or imply performance leadership.

Interpretation of Certification Data

Sustainability and environmental certification labels (e.g., Green Key) are interpreted as:

  • Indicators of baseline compliance with defined criteria

  • Signals of participation in a recognized framework

They are not interpreted as measures of:

  • Absolute environmental performance

  • Comparative sustainability leadership

  • Hotel-level or operator-level ESG outcomes

The absence of certification is not assumed to indicate weak sustainability practices, lack of effort, or poor environmental outcomes.

Comparative Logic

All comparisons across cities, transport systems, or datasets are contextual, not prescriptive.

Raw counts and indicators are interpreted alongside structural factors such as:

  • Regulatory environment

  • Market structure

  • Urban form and density

  • Transport accessibility and infrastructure

This approach reduces the risk of misinterpreting numbers in isolation and emphasizes analytical context over simplistic ranking.

Limitations

Unless explicitly stated otherwise, published analyses do not incorporate:

  • Scope-3 emissions

  • Supply-chain sustainability data

  • Proprietary or non-public ESG disclosures

  • Real-time operational or performance metrics

Where data is unavailable, incomplete, or inconsistent, transparency is prioritized over false precision.

Independence & Non-Endorsement

All research published on Odyssey Discoveries is independent and non-sponsored.

The inclusion of cities, hotels, routes, operators, or datasets does not imply:

  • Endorsement

  • Ranking

  • Commercial relationship

  • Recommendation

This page defines analytical rules, not value judgments.