Research Documentation

Data Methodology

How GrapeCat Chem collects, normalizes, validates, and calculates cross-border chemical market price indexes.

GrapeCat Chem provides normalized market price indexes for research, benchmarking, and statistical analysis. Index values should not be interpreted as executable supplier quotations.

Index Pipeline

How the GrapeCat Chem Index Is Built

Each published comparison passes through a controlled identity, specification, normalization, and validation pipeline.

Raw Market Observations

Collect publicly observable product and pricing records from eligible market sources.

Chemical Identity Matching

Map listings to CAS Number, chemical name, molecular formula, and recognized synonyms.

Specification Matching

Separate observations by purity, grade, concentration, and product specification.

Package Normalization

Normalize compatible package quantities such as mL, L, g, and kg into comparable units.

Currency Normalization

Convert regional pricing into a common comparison currency using a documented FX reference.

Outlier Filtering

Remove clearly anomalous, incomplete, duplicate, or statistically inconsistent observations.

Regional Index Calculation

Calculate representative US and China regional price indexes using qualified observations.

Cross-Border Variance

Calculate the percentage difference between comparable regional indexes.

Raw Data → Identity Matching → Specification Matching → Unit Normalization → FX Normalization → Outlier Filtering → Regional Index → Variance

Calculation Framework

Index Calculation

Regional Price Index

Regional Index = representative normalized price derived from qualified observations within the same chemical identity, specification, grade, and comparable package basis.

The index is a representative statistical value. It is not copied from one supplier listing and is not an executable quotation.

Cross-Border Variance

Variance % = (US Index - China Index) / US Index × 100

Positive variance indicates that the China regional index is lower than the US regional index. Negative variance indicates that the China regional index is higher.

US Market Index

$45.00 / 500 mL

China Market Index

$12.50 / 500 mL

Variance

72.2%

Example only

Comparability Controls

Normalization Rules

Normalization improves comparability only where chemical identity and commercial specification permit a defensible comparison.

CAS Identity: Observations are grouped primarily by CAS Number
Purity: Different purity levels are not automatically treated as equivalent
Grade: AR, HPLC, LC-MS, ACS and other grades are separated where applicable
Package Size: Prices are normalized only where package conversion is considered comparable
Weight / Volume: Mass and volume units are not blindly converted without appropriate chemical context
Currency: Regional prices are converted using the applicable FX reference
Duplicates: Duplicate or materially identical observations may be removed
Outliers: Abnormal observations may be excluded from index calculation

Dimension	Method
CAS Identity	Observations are grouped primarily by CAS Number
Purity	Different purity levels are not automatically treated as equivalent
Grade	AR, HPLC, LC-MS, ACS and other grades are separated where applicable
Package Size	Prices are normalized only where package conversion is considered comparable
Weight / Volume	Mass and volume units are not blindly converted without appropriate chemical context
Currency	Regional prices are converted using the applicable FX reference
Duplicates	Duplicate or materially identical observations may be removed
Outliers	Abnormal observations may be excluded from index calculation

Purity, grade, and specification must remain distinct.GrapeCat Chem does not assume that two listings are directly comparable solely because they share the same CAS Number.

Version Alignment

Published Method Registry

Chemical, Compare, and Bulk return a methodVersion with each regional index. This registry reads the corresponding reviewed explanation through the same backend boundary.

demo-frontend-v2

Development Regional Index V2

DEMOIn current data

Synthetic development method used to exercise the database, Go API, and frontend regional-index contract. Values are not production market intelligence.

Aggregation: Each regional value is a deterministic development result bound to one Chemical specification, package basis, region, currency, and effective period. It exercises the versioned median-oriented contract without asserting a production aggregation run.
Eligibility: Only deterministic Demo observations that match the seeded Chemical identity, specification, package, region, currency, and development quality rules are included.
FX normalization: Development records retain original currencies and method fields. Demo rows using USD directly report no external FX conversion; a production method must identify the observation-date rate and its source.
Outlier handling: The Demo dataset uses deterministic accepted and rejected scenarios to test duplicate, incomplete, and anomalous-input boundaries. It does not claim a finalized production outlier threshold.
Confidence: HIGH, MEDIUM, LIMITED, and UNKNOWN are server-returned development results used to validate the public contract. They are not supplier ratings or guaranteed certainty, and the final production weighting remains version-specific.
Observation and freshness: The development registry models adaptive monitoring: begin quarterly, increase to monthly, weekly, then daily after verified changes, and reduce toward semiannual or annual checks after sustained stability. Each index still carries its own observed, verified, effective, and calculated times.

Registry updated 2026-09-07

demo-full-detail-v6

Full Detail Development Method V6

DEMOIn current data

Synthetic full-detail method used for the 2-Fluorobenzoic Acid multi-basis showcase. Values validate complete History, confidence, supplier coverage, and comparison-basis rendering only.

Aggregation: Each seeded regional basket is a deterministic development result bound to an exact specification and package. Five synthetic supplier representatives exercise the median-oriented aggregation shape.
Eligibility: The full-detail showcase admits only its seeded exact Chemical, specification, package, region, and effective-period observations, preserving each comparison basis independently.
FX normalization: Showcase values use the stored USD target directly and therefore do not assert that a real external FX conversion occurred. Production versions must retain the applicable observation-date FX lineage.
Outlier handling: Deterministic showcase inputs validate lineage and display behavior. The row does not claim a finalized statistical outlier rule for production data.
Confidence: The seeded HIGH result reflects five synthetic eligible suppliers and observations for contract testing. It is explicitly Demo confidence and is not a production quality claim.
Observation and freshness: The showcase provides twelve deterministic monthly history points and explicit calculation times. Future monitoring can apply the adaptive quarterly-to-daily and stable-to-annual policy under a separately implemented crawler scheduler.

Registry updated 2026-09-07

Dataset Assessment

Data Quality & Confidence

Regional-index API responses carry versioned confidence, observation counts, supplier coverage, and calculation timestamps when those values are available.

Assessment factors

Number of qualified observations
Data freshness
Specification consistency
Package comparability
Regional coverage
Price dispersion
Outlier ratio

API confidence vocabulary

High ConfidenceMedium ConfidenceLimited Data

Confidence indicators describe the quality and comparability of the underlying dataset, not the quality of any supplier or chemical product.

Versioned server-side result

Observation Timing

Data Freshness

Chemical price indexes are time-sensitive. Each index carries its own observation, verification, effective, and calculation times; the registry above explains the policy for its exact methodVersion.

Observation count and freshness values shown on Chemical, Compare, and Bulk come from the regional-index API. This page does not publish fixed example counts or dates that could disagree with those records.

Scope Boundaries

What GrapeCat Chem Does Not Do

GrapeCat Chem does not sell chemical substances.
GrapeCat Chem does not provide executable supplier quotations.
GrapeCat Chem does not guarantee that historical or observed prices remain available.
GrapeCat Chem does not automatically treat all products sharing a CAS Number as equivalent.
GrapeCat Chem does not replace regulatory, customs, safety, or procurement due diligence.
GrapeCat Chem indexes should not be interpreted as landed-cost quotations.

Terminology

Key Definitions

Regional Index

Representative normalized market price derived from qualified regional observations.

Qualified Observation

A data point that contains sufficient identity, specification, package, and pricing information for comparison.

Normalized Price

A transformed price used to improve comparability across compatible package sizes, currencies, or units.

Variance

The percentage difference between comparable US and China regional indexes.

Data Freshness

The amount of time since underlying market observations were last refreshed.

Confidence

An indicator describing the statistical coverage and comparability of the underlying dataset.

Explore Market Data

Apply the methodology framework to the current market index directory.

Search by CAS Number