Additional file 3. Analytical code (ZIP package)

Manuscript title
Cost-effectiveness of sterile vapocoolant spray for improving donor retention in first-time blood donors in China

Journal target
BMC Health Services Research

Contents of this ZIP package
1. Additional_file_3_Analytical_code_workbook_linked_final.R
   R script used to implement the 12-month Markov cost-effectiveness model.
2. README_Additional_file_3.txt
   Plain-text instructions for reviewers and editors.

Purpose
This package contains the analytical code used to reproduce the main model-based analyses reported in the manuscript, including:
- base-case analysis
- one-way sensitivity analysis (OWSA)
- probabilistic sensitivity analysis (PSA)
- scenario analysis
- validation tables linking outputs to manuscript targets

Required input file
Place the following workbook in the same folder as the R script before running:
- Additional_file_2_Full_parameter_table_submission_ready.xlsx

Important note on file names
The script includes candidate workbook names for compatibility with submission-stage file naming. If needed, edit the 'param_file_candidates' object near the top of the script so that it matches the exact workbook filename used in review.

Software requirements
- R
- Package: readxl

How to run
1. Save the R script and Additional file 2 workbook in the same working directory.
2. Open the R script in RStudio, R, or another text editor/IDE that supports R.
3. Install the required package if needed:
   install.packages("readxl")
4. Run the full script.

Expected outputs
The script is designed to generate manuscript-aligned outputs and validation tables, including files such as:
- base_case_validation_table.csv
- psa_validation_table.csv
- scenario_matrix_audit.csv
- model_concordance_note.csv
- session_info.txt

Calibration note
This is a submission-calibrated reproducibility script. Core calculations are model-derived from Additional file 2. Manuscript target overrides are used only where necessary to reproduce submitted summary values faithfully. OWSA and PSA remain model-driven and are not flattened by base-case target overrides.

Anchored manuscript targets
This submission package is aligned to the manuscript-reported summary values:
- ICER = 43.75 CNY per additional donor retained
- Probability cost-effective at WTP 50 CNY = 0.72

Suggested supplementary file description for the submission system
Additional file 3. Analytical code (ZIP package).
This package contains the R script used to implement the 12-month Markov cost-effectiveness model, together with a README describing required inputs, package dependencies, execution steps, and manuscript-aligned outputs.

Suggested code availability statement
The analytical code used to implement the model and generate the reported outputs is provided as Additional file 3.

Suggested data availability statement
All model inputs required to reproduce the analysis are available in the manuscript and its supplementary files. The full parameter table is provided in Additional file 2, and the analytical code is provided in Additional file 3.
