{
  "id": "cost-driver-index",
  "title": "Radon Mitigation Cost Driver Index",
  "description": "What actually moves a radon mitigation quote, in which direction, and by how much relative to a baseline job — a structured cost model for comparing two bids on the same house.",
  "version": "1.0.0",
  "status": "published",
  "provenance": "editorial-taxonomy",
  "license": "CC BY 4.0 — reuse with attribution to Radon Connect and a link to the dataset page.",
  "published": "2026-07-29",
  "canonical": "https://radonconnect.com/datasets/cost-driver-index/",
  "schema": [
    {
      "key": "driver",
      "label": "Cost driver",
      "type": "string",
      "description": "The variable that moves the price."
    },
    {
      "key": "category",
      "label": "Category",
      "type": "enum",
      "values": [
        "foundation",
        "access",
        "design",
        "equipment",
        "compliance",
        "verification"
      ],
      "description": "Which part of the job the driver belongs to."
    },
    {
      "key": "direction",
      "label": "Direction",
      "type": "enum",
      "values": [
        "increases",
        "decreases",
        "varies"
      ],
      "description": "Effect on the quote relative to a baseline job."
    },
    {
      "key": "magnitude",
      "label": "Relative magnitude",
      "type": "enum",
      "values": [
        "minor",
        "moderate",
        "major"
      ],
      "description": "Size of the effect relative to a baseline poured-basement retrofit. A relative class, deliberately not a dollar figure."
    },
    {
      "key": "observable",
      "label": "Observable before quoting",
      "type": "boolean",
      "description": "Whether a homeowner can assess this themselves before contractors arrive."
    },
    {
      "key": "why",
      "label": "Why it moves the price",
      "type": "string",
      "description": "The mechanism."
    }
  ],
  "methodology": {
    "question": "When two radon mitigation quotes on the same house differ, which variable explains the gap — and in which direction?",
    "construction": [
      "Drivers were derived from the design decisions a mitigation scope must specify: suction placement and count, routing, sealing scope, fan selection, electrical, and verification.",
      "Direction and magnitude are stated relative to a baseline job — a single-zone poured basement with accessible slab, interior routing, and one suction point.",
      "Magnitude is a three-level relative class, deliberately not a dollar amount or a percentage. We hold no quote data and will not imply that we do."
    ],
    "inclusion": [
      "A driver qualifies when it changes the scope of work rather than only the contractor’s margin.",
      "Market factors — local labour rates, competition, seasonality — are excluded because they vary by area and we have no basis to quantify them."
    ],
    "limitations": [
      "This dataset contains no prices and cannot be used to estimate one. Its purpose is to explain a difference between two real quotes on a real house.",
      "Magnitude classes are editorial judgements informed by scope content, not measurements. Two contractors could reasonably rank adjacent drivers differently.",
      "A driver marked observable can be assessed by a homeowner; it does not follow that a homeowner should skip the site visit."
    ]
  },
  "rowCount": 18,
  "rows": [
    {
      "driver": "Number of distinct soil-contact zones",
      "category": "foundation",
      "direction": "increases",
      "magnitude": "major",
      "observable": true,
      "why": "Each zone — basement slab, crawl space, slab-on-grade addition — may need its own suction or membrane, and a bid covering only one zone has priced a different house."
    },
    {
      "driver": "Crawl space requiring sealed membrane",
      "category": "foundation",
      "direction": "increases",
      "magnitude": "major",
      "observable": true,
      "why": "Membrane material scales with area and the labour happens in a confined space, which is slow regardless of hourly rate."
    },
    {
      "driver": "Crawl space headroom and access",
      "category": "access",
      "direction": "varies",
      "magnitude": "moderate",
      "observable": true,
      "why": "Eighteen inches of clearance with a small hatch and ductwork in the way multiplies the hours the same square footage takes."
    },
    {
      "driver": "Finished basement over the slab",
      "category": "access",
      "direction": "increases",
      "magnitude": "moderate",
      "observable": true,
      "why": "Suction placement is constrained to where the slab can be reached, routing must use chases, and any opened surface has to be made good."
    },
    {
      "driver": "Suction points indicated by diagnostic",
      "category": "design",
      "direction": "increases",
      "magnitude": "major",
      "observable": false,
      "why": "Each additional point is another core, more pipe, and more sealing. How many are needed is measured, not assumed."
    },
    {
      "driver": "Sub-slab material permeability",
      "category": "design",
      "direction": "varies",
      "magnitude": "moderate",
      "observable": false,
      "why": "Clean aggregate lets a single point serve a large slab; tight or inconsistent fill limits how far the pressure field extends."
    },
    {
      "driver": "Interior chase available for the riser",
      "category": "access",
      "direction": "decreases",
      "magnitude": "moderate",
      "observable": true,
      "why": "An internal route through a closet or mechanical chase to an attic fan is usually tidier and cheaper than an exterior run with weatherproofing."
    },
    {
      "driver": "Exterior routing on a visible elevation",
      "category": "access",
      "direction": "increases",
      "magnitude": "minor",
      "observable": true,
      "why": "Longer pipe, exterior fastening and sealing, and often paint to match trim."
    },
    {
      "driver": "Fan matched to measured static pressure",
      "category": "equipment",
      "direction": "varies",
      "magnitude": "minor",
      "observable": false,
      "why": "Right-sizing changes the unit price modestly and the operating cost and noise substantially. Oversizing is not an upgrade."
    },
    {
      "driver": "Open sump pit requiring sealed lid",
      "category": "design",
      "direction": "increases",
      "magnitude": "minor",
      "observable": true,
      "why": "A sealed, gasketed lid is inexpensive and often converts the pit into an efficient suction point, so it can reduce the total."
    },
    {
      "driver": "Untrapped or dried floor drains",
      "category": "design",
      "direction": "increases",
      "magnitude": "minor",
      "observable": true,
      "why": "Each is a direct path to the sub-slab layer that bleeds suction; the remedies are cheap but must be in scope."
    },
    {
      "driver": "Hollow block foundation walls",
      "category": "foundation",
      "direction": "increases",
      "magnitude": "moderate",
      "observable": true,
      "why": "Block cavities act as vertical channels connected to soil, so sealing the open top course becomes a line item."
    },
    {
      "driver": "Dedicated electrical circuit and disconnect",
      "category": "compliance",
      "direction": "increases",
      "magnitude": "minor",
      "observable": false,
      "why": "Fans run continuously and need proper circuit provision; distance to the panel drives the cost."
    },
    {
      "driver": "Local permit required",
      "category": "compliance",
      "direction": "increases",
      "magnitude": "minor",
      "observable": false,
      "why": "A local building-department question rather than a state one. The scope should name who pulls and pays for it."
    },
    {
      "driver": "Post-mitigation verification test included",
      "category": "verification",
      "direction": "increases",
      "magnitude": "minor",
      "observable": false,
      "why": "A small line that is the deliverable of the whole job. Its absence is the most common reason a bargain bid is cheaper."
    },
    {
      "driver": "Remedy clause for a failed verification",
      "category": "verification",
      "direction": "increases",
      "magnitude": "moderate",
      "observable": false,
      "why": "A scope committing to an outcome prices the risk of returning. A scope committing only to an installation does not, and moves that risk to you."
    },
    {
      "driver": "Exposed soil section behind finished wall",
      "category": "foundation",
      "direction": "increases",
      "magnitude": "moderate",
      "observable": false,
      "why": "Discovered on a site visit rather than from photographs, and usually requires membrane work the original bid did not contemplate."
    },
    {
      "driver": "Radiant tubing embedded in the slab",
      "category": "design",
      "direction": "increases",
      "magnitude": "moderate",
      "observable": true,
      "why": "Loops must be located before coring, which adds survey time and constrains where suction can go."
    }
  ]
}