The methodology ladder
Every Plexus result fits one of four categories: a desktop calculation, a practitioner's judgment, specialist work, or an agency determination. The category tells you who is responsible and what must happen before the item is complete.
Plexus Impact helps professionals prepare and organize environmental-review work; it does not issue determinations, which remain with the responsible agency, and is not legal advice.
The four rungs
The rungs do not measure difficulty or confidence. They show whether Plexus, the practitioner, a specialist, or the lead agency is responsible for the item.
Plexus is answerable for the arithmetic.
On this rung, for example: Trip generation and the CEQR screening thresholds; Water demand and sewage generation in gallons per day; Solid waste in tons per week; Energy in source BTU per year; School seats, distances to mapped features, lot and zoning readouts.
You are answerable. Plexus assembles what you need to decide.
On this rung, for example: Which study areas the review should cover, and how wide; Whether a screening result warrants a fuller analysis; What comparable reviews imply for this site; A project fact we do not hold, such as an employee count or a unit mix; Which of the open items must be resolved before filing.
A licensed or qualified professional is answerable.
On this rung, for example: Wetland delineation and a jurisdictional determination; Phase I ESA, and Phase II sampling if it is indicated; Ambient sound measurements; Peak-hour turning-movement counts, signal timing and lane geometry; Archaeological and architectural resource investigation.
The lead agency is answerable. Never Plexus.
On this rung, for example: The determination of significance, negative or positive; Whether an environmental impact statement is required; Scope adequacy, and acceptance of a filing; Lead agency designation itself.
Classify a result
Start with the first question and stop at the first yes. This places each item on one rung, even when several people contribute to the work.
Does a lead agency have to rule on it before it is settled?
Yes. Rung 4. Plexus can organize the record for it and can show what comparable reviews received. It states no expectation about the outcome.
Does it need work only a licensed or qualified professional can sign?
Yes. Rung 3. Plexus names the request and holds the result. It does not estimate what the result will be.
Does it turn on a judgment, or on a project fact that only your team holds?
Yes. Rung 2. Plexus assembles what it has, states the question, and names what is missing. The judgment is yours, and so are the project facts behind it.
Is it arithmetic over a published method and data on file, reproducible by hand?
Yes. Rung 1. Plexus computed it, and it is a planning estimate until the method behind it has cleared a stated bar.
If a result does not make its rung clear, please tell us.
Rung 1, in detail
Plexus can calculate a result when the method and the figures it needs are on file. That alone does not show the result agrees with a study prepared by a professional.
We label every calculated result as a planning estimate until it has been tested against filed studies and met a published standard. We show the standard, sample, result, and limitations for each test.
One of 21 study types has a calculation that met a standard set before testing. That result must be tested again under the current sample-size requirement. All other calculated results are labelled as planning estimates.
| Solid waste generation | Met the bar, on too few cases | Tested against 5 filed studies. The median difference was 6.9%, compared with a standard of 15% set before testing. |
| Traffic | Did not meet the bar | Tested against 10 filed studies. The median difference was 76.4%, compared with a standard of 30% set before testing. |
| Water demand and sanitary flow | Did not meet the bar | Tested against 8 filed studies. The median difference was 17.1%, compared with a standard of 15% set before testing. |
| Energy demand | Did not meet the bar | Tested against 5 filed studies. The median difference was 65.1%, compared with a standard of 30% set before testing. |
Previously passed a five-case check; not yet tested against the current eight-case minimum. The minimum was raised to eight cases on August 27, 2026. The solid waste generation test predates that change and must be run again before it can meet the current standard.
Not yet compared at all: Traffic, Community facilities, Noise, Open space ratio. These calculations include their methods and inputs, but they have not been tested against filed studies.
Saved snapshot generated September 9, 2026. Study list version 2026-08-24. The table below checks for current figures and identifies whether it is showing live data or the snapshot.
The table below shows what Plexus can calculate or organize for each study type. If a calculation did not meet its test standard, the table reports that result.
Plexus currently supports 21 technical study types. 8 include a planning calculation, and 1 of those has met the current test standard. The other 13 are organized as sourced review work rather than calculations.
Plexus calculates the result from a published method and the project's own figures. The calculation met its published test standard against filed professional studies.
| Study | Source or method | Comparison with filed studies |
|---|---|---|
| Solid waste generation | Source material on file. CEQR Ch. 14, 22 entries, every quote located in the source PDF Manual reconciliation with the published source is pending. | Passed, on too few cases. Tested against 5 filed studies. The median difference was 6.9%, compared with a standard of 15% set before testing. Previously passed a five-case check; not yet tested against the current eight-case minimum. |
Plexus calculates the result from published methods and rates. The result carries the figures it used and their sources, but testing against filed studies is not complete.
| Study | Source or method | Comparison with filed studies |
|---|---|---|
| Traffic trip generation and the Ch. 16 screen | Source material on file. CEQR Ch. 16, 206 entries, every quote located in the source PDF Manual reconciliation with the published source is pending. | Did not meet the bar. Tested against 10 filed studies. The median difference was 76.4%, compared with a standard of 30%. |
| Traffic intersection level of service | Source material on file. hcm_los.py, los_screen.py | Comparison with filed studies is pending. Specialist or field input: Peak-hour turning-movement counts, Signal timing and lane geometry. |
| Community facilities schools | Source material on file. CEQR Ch. 6, 26 entries, every quote located in the source PDF Manual reconciliation with the published source is pending. | Comparison with filed studies is pending. |
| Water demand and sanitary flow | Source material on file. CEQR Ch. 13, 13 entries, every quote located in the source PDF Manual reconciliation with the published source is pending. | Did not meet the bar. Tested against 8 filed studies. The median difference was 17.1%, compared with a standard of 15%. |
| Energy demand | Source material on file. CEQR Ch. 15, 5 entries, every quote located in the source PDF Manual reconciliation with the published source is pending. | Did not meet the bar. Tested against 5 filed studies. The median difference was 65.1%, compared with a standard of 30%. |
| Noise CEQR screening and attenuation | Source material on file. CEQR Ch. 19, 20 entries, every quote located in the source PDF Manual reconciliation with the published source is pending. | Comparison with filed studies is pending. Specialist or field input: Ambient sound measurements. |
| Open space ratio | Source material on file. CEQR Ch. 7, 32 entries, every quote located in the source PDF Manual reconciliation with the published source is pending. | Comparison with filed studies is pending. |
Plexus identifies the study question, relevant rules or guidance, and material needed. The final column lists any missing information or specialist work.
| Study | Source or method | Information or work still needed |
|---|---|---|
| Greenhouse gas emissions | Source material is still needed. The published method is pending addition to the workspace. | the method is not held yet (the published method) |
| Environmental justice screen | Source material is still needed. Required source: The CP-29 screening steps, and a method for the consideration ECL 8-0113 requires. The State's designated-DAC list is no longer outstanding: `dac.screen` reads it at request time. What is missing is a method, and CEQR Ch.23 s 300 records that DEC's rulemaking implementing 6 NYCRR 617 was not final when the chapter was written, so no published one exists to encode. | Missing input: EPA EJScreen indicators |
| Land use and zoning consistency | Source material is still needed. Required source: District use and bulk rules as data — NYC Zoning Resolution first, then the municipal codes behind the Part VII campaign | Missing input: Use and bulk rules for that district |
| Shadows | Source material is still needed. Required source: CEQR Ch. 8 shadow screening geometry (tier 1/2/3 screens and the four analysis days) | Missing input: Building height, Building footprint |
| Transit demand | Source material is still needed. Required source: CEQR Ch. 16 modal split and transit trip assignment factors, encoded as a catalog | Missing input: Transit stops, routes and headways |
| Stormwater initial sizing | Source material is still needed. Required source: NYSDEC Stormwater Management Design Manual — water quality volume, runoff reduction, sizing criteria | Missing input: Design rainfall depths |
| Air quality screening | Source material requires verification. The published method will be cited in the workspace after reconciliation with its source catalog. | Missing input: Parking spaces, Heating fuel and floor area, Distance to the nearest receptor |
| Climate and flood resilience | Source material is still needed. Required source: NYS sea level rise projections (6 NYCRR Part 490) and the ClimAID design tables | Missing input: Sea level rise projection for the region |
| Wetlands, habitat and species screening | Source material on file. geodata.py, spatial_analysis.py | Needs from the field: Wetland delineation, Natural Heritage response, and any survey it asks for |
| Historic and archaeological screening | Source material on file. geodata.py | Missing input: Archaeological sensitivity |
| Hazardous materials screening | Source material on file. geodata.py | Needs from the field: Phase I ESA findings, Phase II sampling results |
| Socioeconomic conditions and displacement | Source material is still needed. Required source: CEQR Ch. 5 preliminary assessment thresholds (direct and indirect residential and business displacement), encoded as a catalog | the method is not held yet (CEQR Ch. 5 preliminary assessment thresholds (direct and indirect residential and business displacement), encoded as a catalog) |
| Visual and aesthetic resources | Source material is still needed. Required source: A viewshed method: terrain, the structure's envelope, and the convention for choosing representative viewpoints. CEQR Ch. 10 for the city and NYSDEC Program Policy DEP-00-2 for the State describe what an assessment contains; neither publishes a computation to encode. | Needs from the field: The structure's height and bulk, Panel height, row spacing and screening, for an array, Photographs from agreed viewpoints |
Showing a saved snapshot, generated September 9, 2026, while current figures are being checked. Study list version 2026-08-24. The following rows also draw figures from public services queried at the time of a screening rather than from data held here, so those lookups are unconfirmed while this page is showing stored figures: Traffic, Community facilities, Water demand and sanitary flow, Solid waste generation, Open space ratio, Environmental justice screen, Shadows, Transit demand, Stormwater, Climate and flood resilience, Wetlands, habitat and species screening, Historic and archaeological screening, Hazardous materials screening, Socioeconomic conditions and displacement, Visual and aesthetic resources.
The measurement record includes the test runs, cases, limitations, and withdrawn results. Read the measurement record.
Rung 4
An earlier version of Plexus used comparable reviews to estimate how an agency might decide. We removed that feature after testing showed that it did not provide a reliable prediction.
Plexus still shows comparable reviews because they can help a practitioner understand the process and investigate relevant issues. It does not turn those outcomes into a prediction. The lead agency makes the determination for the project before it.
Why the record is kept this way
Each item keeps its project facts, source, and next action. A calculation carries the figures it used, the method, the assumptions, and the result. A practitioner question carries the regulation or guidance behind it. Specialist work carries the request and the finished study. Agency decisions include the filing, response, and date.
This lets the team see what changed, what supports a draft, and what remains open. It also lets a reviewer trace any result back to its source.
Scope
Plexus is designed for SEQR statewide and CEQR in New York City. It is most useful at the beginning of a project, when the team needs to establish the review path and the work plan, and it continues to hold the record as the project changes.
Something on this page wrong or out of date? Tell us.
Plexus Impact helps professionals prepare and organize environmental-review work; it does not issue determinations, which remain with the responsible agency, and is not legal advice.