> ## Documentation Index
> Fetch the complete documentation index at: https://docs.n-3.co.uk/llms.txt
> Use this file to discover all available pages before exploring further.

# Create a benchmark report using the standard model

## Overview

Generates a comprehensive benchmark report using N3's standard cost prediction model. This endpoint creates cost forecasts based on similar projects, providing statistical analysis with confidence intervals.

## Benchmark Types

Supports multiple benchmark approaches:

* **STANDARD** - Single development benchmarking
* **COMPOSITE** - Multi-development project analysis
* **PARTIAL** - Individual development within composite projects

## Model Capabilities

### Cost Prediction Features

* Statistical modeling using 50+ weighted factors
* Confidence intervals (typically 75-85% confidence)
* Real-time prediction updates
* Quality assessment and validation

### Input Requirements

* Project characteristics (GIFA, location, features)
* Development type and building specifications
* Site constraints and procurement details
* Budget data and timeline information

## Quality Assessment

Benchmarks are evaluated through multiple quality checks:

✅ **Data Completeness** - Presence of out-turn cost data\
✅ **Statistical Validity** - Average costs within confidence intervals\
✅ **Similarity Threshold** - Combined scores ≤30 points for 3 projects\
✅ **Geographic Relevance** - Location and time index alignment

## Usage Examples

### Standard Benchmark Request

```json theme={null}
{
  "projectId": "12345",
  "benchmarkType": "STANDARD",
  "includeComparisons": true,
  "generatePredictions": true
}
```

### Composite Project Request

```json theme={null}
{
  "projectId": "12345", 
  "benchmarkType": "COMPOSITE",
  "developments": ["dev1", "dev2"],
  "hybridSupport": true
}
```

## Response Structure

Returns comprehensive benchmark data including:

* Cost predictions with confidence ranges
* Similar project comparisons and scores
* Quality indicators and health ratings
* Statistical model metadata

## Related Endpoints

* **[Get Similar Projects](/api-reference/benchmark/get-the-three-closest-similar-projects)** - Find comparable projects
* **[Create Snapshot](/api-reference/benchmark/create-a-benchmark-snapshot-for-the-project)** - Save benchmark results
* **[Get Project Report](/api-reference/benchmark/get-a-benchmark-report-using-the-standard-model-from-project-id)** - Retrieve existing predictions


## OpenAPI

````yaml post /benchmark
openapi: 3.0.0
info:
  title: Naismith Analytics API
  description: The N3 API
  version: '0.1'
  contact: {}
servers: []
security: []
tags: []
paths:
  /benchmark:
    post:
      tags:
        - Benchmark
      summary: Create a benchmark report using the standard model
      operationId: createFromSpec
      parameters: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/BenchmarkSpecDto'
      responses:
        '200':
          description: ''
          content:
            application/json:
              schema:
                type: array
                items:
                  $ref: '#/components/schemas/BenchmarkDto'
      security:
        - x-api-key: []
        - bearer: []
components:
  schemas:
    BenchmarkSpecDto:
      type: object
      properties:
        total_gifa:
          type: number
          example: 1500000
        individual_units:
          type: number
          example: 12
        site_area:
          type: number
          example: 15000
        location_index:
          type: number
          example: 115
        start_date:
          type: string
          description: Months from now until construction starts
          example: '2024-11-01'
        total_net_internal_area:
          type: number
          description: Net internal area (NIA)
          example: 1000
        site_max_floors_above_ground:
          type: number
          description: Number of floors above ground
          example: 2
        site_max_floors_below_ground:
          type: number
          description: Number of floors below ground
          example: 1
        detached_garage_spaces:
          type: number
          description: Number of parking garages (detached)
          example: 0
        basement_parking_spaces:
          type: number
          description: Number of basement parking spaces
          example: 0
        integral_garage_spaces:
          type: number
          description: Number of parking garages (integral)
          example: 0
        undercroft_parking_spaces:
          type: number
          description: Number of undercroft parking spaces
          example: 0
        car_ports:
          type: number
          description: Number of carports
          example: 0
        surface_parking:
          type: number
          description: Number of surface parking spaces
          example: 0
        primary_building_function:
          type: string
          description: Primary building function
          enum:
            - residential
            - residential_mixed_use
            - student_accommodation
          example: residential
        primary_building_process:
          type: string
          description: Primary building process
          enum:
            - new_build
            - refurbishment_no_alterations
            - extension
            - refurbishment_with_alterations
            - permitted_development
            - air_rights
          example: new_build
        procurement_arrangements:
          type: string
          description: Procurement arrangements
          enum:
            - main_contractor_design_build
            - main_contractor_traditional
            - self_build
          example: main_contractor_design_build
        demolition:
          type: number
          description: Cost of demolition
          example: 0
        contaminated_soil_removal:
          type: number
          description: Cost of contaminated soil removal
          example: 0
        piling:
          type: number
          description: Cost of piling
          example: 0
        basement_construction:
          type: number
          description: Cost of basement construction
          example: 0
        structural_alterations:
          type: number
          description: Cost of structural alterations
          example: 0
        concrete_frame:
          type: number
          description: Cost of concrete frame
          example: 0
        lift_escalator:
          type: number
          description: Cost of lift escalator
          example: 0
        retaining_walls:
          type: number
          description: Cost of retaining walls
          example: 0
        diversion_of_services:
          type: number
          description: Cost of services diversion
          example: 0
        drainage_pumping_station:
          type: number
          description: Cost of drainage pumping station
          example: 0
        electricity_sub_station:
          type: number
          description: Cost of electricity sub-station
          example: 0
        sprinkler_system:
          type: number
          description: Cost of sprinkler system
          example: 0
        party_wall:
          type: number
          description: Cost of party wall
          example: 0
        balconies_terraces_winter_gardens:
          type: number
          description: Cost of balconies and terraces
          example: 0
        basement_car_parking:
          type: number
          description: Cost of basement car parking
          example: 0
    BenchmarkDto:
      type: object
      properties:
        totals:
          type: number
          description: Total cost (sum)
          example: 2571000
        external_works_variation:
          type: number
          description: External works variation
          example: 100000
        total_including_external_works:
          type: number
          description: Total including external works
          example: 2571000
        total_adjusted_value:
          type: number
          description: Total adjusted value
          example: 2991359
        adjusted_cost_per_m2:
          type: number
          description: Adjusted cost per m2 (GIFA)
          example: 1994
        lower_limit:
          type: number
          description: Lower limit for adjusted cost per m2
          example: 1595
        upper_limit:
          type: number
          description: Upper limit for adjusted cost per m2
          example: 2592
        _meta:
          $ref: '#/components/schemas/BenchmarkMetaDto'
      required:
        - totals
        - external_works_variation
        - total_including_external_works
        - total_adjusted_value
        - adjusted_cost_per_m2
        - lower_limit
        - upper_limit
        - _meta
    BenchmarkMetaDto:
      type: object
      properties:
        adjustment_percentage:
          type: number
          description: Percentage adjustment from adjustments
          example: 0.35
        external_works_percentage:
          type: number
          description: Percentage adjustment from external works
          example: 0.25
        strength:
          type: number
          description: >-
            Strength of the benchmark is based on the number of factors used in
            the calculation
          example: 75
        profiled_strength:
          type: number
          description: >-
            The weight of the profiled factors added in the benchmark
            calculation
          example: 2.5
        location:
          description: The identified location used for calculations
          allOf:
            - $ref: '#/components/schemas/BenchmarkLocationMetaDto'
      required:
        - adjustment_percentage
        - external_works_percentage
        - strength
        - profiled_strength
        - location
    BenchmarkLocationMetaDto:
      type: object
      properties:
        county:
          type: string
          description: County name
          example: London
        index:
          type: number
          description: Location index
          example: 100
      required:
        - county
        - index
  securitySchemes:
    x-api-key:
      type: apiKey
      in: header
      name: x-api-key
    bearer:
      scheme: bearer
      bearerFormat: JWT
      type: http

````