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One in-house workflow across
cleaning → modeling → weighting

Three professional R projects for survey and assessment data, developed in-house with full IP ownership and no client data.

Raw response data
DCCData cleaning IRTCMeasurement modeling WFCSurvey weighting
Trustworthy conclusions
CASE 01
DCC
Rule-driven, fully auditable data cleaning
Data cleaning Rule-driven Cell-level audit Reproducible GPL ≥ 2
■ PROBLEM

Survey and assessment data often arrive in multiple formats and encodings, with out-of-range values, missing responses, straight-lining, timing anomalies, and form-specific item identifiers. Ad-hoc scripts bury correction logic in code, making it hard to review why a value changed or reproduce the full run.

■ SOLUTION
  • Versioned rules run range, set, and expression checks plus detectors for missingness, straight-lining, response time, trap items, and score anomalies.
  • Detection and execution are separate: exclude, set-NA, recode, and flag actions must map explicitly to rules, while unhandled findings remain visible.
  • Raw data stay immutable; every change records old and new values, rule, method, and finding_id, while manifests and hashes support verified reruns.
  • Common tabular and statistical formats, chunked processing, scoring, multi-form item-bank alignment, and self-contained HTML reports are supported.
■ RESULTS & VALUE

DCC turns “cleaned data” into an explainable, traceable, rerunnable data product, giving project leads, analysts, and reviewers the same evidence chain.

What it means for your project: A defensible cleaning pipeline can be tailored to your data rules without turning project-specific decisions into opaque code.
CASE 02
IRTC
High-performance item response theory estimation
Item response theory C++ / Rcpp Low-memory streaming GPL ≥ 2
■ PROBLEM

Large-scale assessments may involve hundreds of thousands or millions of respondents, many items, and multiple dimensions. Traditional IRT software can become impractical because of memory use, runtime, or limited extensibility.

■ SOLUTION
  • Supports Rasch/1PL, PCM, RSM, 2PL, and GPCM models; unidimensional and between-item multidimensional structures; latent regression, multiple groups, case weights, and EAP scoring.
  • Parallel E-steps, person-block streaming, dimension decomposition, analytical gradients, hybrid Newton updates, and automatic engine routing are designed for scale.
  • Optional quadrature pruning reports measured approximation error; exact computation remains the default and never changes silently.
■ RESULTS & VALUE

Grid, streaming, and automatic engines make routine analyses simple while keeping large-data execution controllable. Chinese and English manuals support handover to applied teams.

What it means for your project: IRTC is the core proof of WEIAN's measurement expertise and large-scale engineering, and can serve as an extensible engine for custom assessment projects.
CASE 03
WFC
Precheck-first survey weighting and calibration
Survey weighting Raking Post-stratification Diagnostics GPL ≥ 2
■ PROBLEM

Survey-weighting scripts often fail silently when sample and target categories differ, cells are too thin, group totals drift after trimming, or multiple target sources use inconsistent schemas. A final weight column alone cannot show what was checked or which decisions were made.

■ SOLUTION
  • One canonical target accepts population data, weighted reference samples, or manual margins and compares sample and target before computing weights.
  • A declared collapse ladder exposes incompatibilities and thin cells first, then applies reviewed category merges consistently to sample and target.
  • Raking and post-stratification share one dispatcher and result contract; the guided path never bypasses a blocking precheck.
  • Diagnostics, a decision ledger, bilingual reports, and audit exports make each calibration run reviewable.
■ RESULTS & VALUE

WFC turns one-off weighting scripts into a standard precheck → execute → diagnose workflow, reducing the risk of weights that converge numerically while drifting from the intended population contract.

What it means for your project: Your weighting workflow becomes reviewable from target construction through diagnostics, rather than ending with an unexplained column of numbers.
* All three projects are developed in-house by WEIAN with full IP ownership. Case studies contain no client project names or sensitive data.

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