# Who does what: preparer roles in a cost segregation study The roles behind a cost segregation study, from field analyst and estimator to classification lead, reviewer and tax adviser, and how they divide responsibility. ## Short answer A cost segregation study is usually the work of several people, even in a small practice. Someone gathers the evidence and walks the site. Someone quantifies and prices the components. Someone decides, item by item, what the law makes each component and writes the reasons down. Someone who did none of that reviews the whole thing. And someone else, the client's tax adviser, applies the study to the return and is responsible for it. The IRS's Audit Techniques Guide says there are no prescribed qualifications for preparers but expects a quality study to identify who prepared it and what they bring, and lists the elements each role has to deliver. This article describes the roles, what each is accountable for, and where the lines between them matter. It is general education for people entering the work, not tax advice. ## The roles | Role | Delivers | Typical background | Accountable for | |---|---|---|---| | Engagement lead | Scope, engagement letter, client and adviser contact, the final report | Experienced practitioner | The study as a whole; its limitations; the preparer identification the IRS guide expects | | Field analyst | Site visit, photographs, interviews, measurements, document index | Construction, engineering, appraisal, or trained entrant | What is actually there and what was requested and received | | Estimator | Take-offs, unit costs, indirect cost allocation, cost source documentation | Construction estimating, engineering | The cost of each component and its support | | Classification lead | The legal analysis for each component's class; the asset list | Tax, law, or practitioner with the legal training | Why each item is section 1245 or section 1250 property and its recovery period | | Reconciler | The reconciliation to basis; the tie to the ledger | Accounting, audit | That everything is counted once and differences are explained | | Reviewer | Independent review of evidence, classifications, costs and reconciliation | Senior practitioner who did not do the work | Errors found before the report issues | | Tax adviser (client's) | Return position, elections, Form 3115 where needed, passive activity and state analysis | CPA, enrolled agent, attorney | The return, under their professional rules | In a one-person practice the first six roles collapse into one person, and the reviewer role is the one most often lost. That is the reason good solo practitioners arrange peer review. ## What the IRS guide asks of the roles together The guide's list of principal elements reads like a division of labor. Documentation and interviews come from the field. Unit costs and take-offs come from the estimator. The legal analysis comes from the classification lead. The organized asset list and the reconciliation come from the reconciler. The methodology description and the preparer identification come from the engagement lead. Consideration of related aspects, such as a change in accounting method, is the point where the practitioner's work meets the adviser's. The guide's statement that an engineering-based study is generally more reliable, with cost estimating experience and legal knowledge as further criteria, is also a statement about roles. A team that has all three is delivering what the guide describes; a team missing one is delivering something less, whatever its size. ## Where the lines matter ### Between the practitioner and the adviser The practitioner classifies and costs. The adviser decides the return position, makes the elections, files any change in accounting method and applies the passive activity and state rules. Advisers who practice before the IRS work under Circular 230, which sets standards for competence, diligence, return positions and written advice; a practitioner who begins telling the client what to claim has crossed into that territory. The engagement letter should say who does what. ### Between the classification lead and the estimator Cost and class are separate questions and are answered most reliably by people who are not trying to make the other one come out a particular way. An estimator who knows the classification lead wants a large 5-year line has a reason to price it generously; a classification lead who knows the estimate is thin has a reason to stretch a category. Keeping the roles distinct, or at least keeping the reasoning for each written separately, guards against both. ### Between the preparer and the reviewer The reviewer's value is independence. A review by the person who did the work finds the errors that person was already going to find. The reviewer reads the reconciliation, the land split and the asset list, then samples classifications and costs against the evidence, and writes findings the preparer must answer. The same principle governs NBCSS's own processes: reviewers, examiners and decision-makers hold recorded roles, and no one reviews their own work or decides their own appeal. ## What each role should be able to show - **Field analyst:** a dated site record, photographs keyed to the asset list, the document index with requests and receipts. - **Estimator:** take-off sheets, unit-cost sources and dates, adjustments, the indirect cost schedule. - **Classification lead:** a written reason, with authority, for each classification, and a list of the items where judgement was exercised. - **Reconciler:** the reconciliation page and the ledger tie. - **Reviewer:** written findings and the preparer's responses. - **Engagement lead:** the engagement letter, the methodology section, the limitations section, and the preparer identification. A file that contains those artifacts can be examined without the people in the room. That is the test. ## How the roles work through one engagement On a small acquisition study the sequence is usually this. The engagement lead scopes the work with the owner and the adviser, confirms which documents exist and issues the engagement letter. The field analyst requests the documents, builds the index, visits the site with the drawings in hand, photographs each component and interviews the manager about what equipment serves what. The estimator takes the drawings and field notes, measures quantities, prices them from records where they exist and from documented unit costs where they do not, and prepares the indirect cost schedule. The classification lead works from the same asset list and writes the reason for each class, flagging the items where judgement was exercised. The reconciler ties the whole list to the capitalized basis and to the adviser's ledger, and lists the differences. The reviewer, who has touched none of it, reads the reconciliation, the land split and the asset list, samples the classifications and costs against the file, and writes findings. The engagement lead answers the findings, revises, reconciles again and issues the report with the methodology, the limitations and the preparer identification. The adviser takes it from there. In a two-person shop the same sequence happens with the roles traded back and forth, and the reviewer is borrowed. ## For someone entering the work Most entrants start in the field or in estimating, because those roles can be learned by doing under supervision. Classification comes next, because it requires the law and takes longer. Reconciliation is learned alongside both. Review is the last role, because it requires having made and corrected enough errors to recognize them in someone else's work. A career plan that names which role you hold today and which you are preparing for is more useful than a title. ## What people ask on Reddit and other forums The searches that lead people to these threads are usually phrased "cost segregation analyst", "who prepares a cost segregation study". Career threads on r/Accounting and r/civilengineering, and "cost segregation reddit" searches, ask who actually does what inside a study. From the sources below: **"What does a cost segregation engineer actually do all day?"** Site visits, drawings, take-offs and cost estimates, and increasingly classification once the law is learned. The legal analysis and the report's judgement sections are usually a senior practitioner's. **"Does a study need an engineer?"** The IRS prescribes no qualifications; it describes engineering-based studies as generally more reliable and names cost estimating and legal knowledge as further criteria. A team without an engineer needs equivalent construction and cost competence. **"Who signs the report?"** The engagement lead, by name, with credentials and experience, as the IRS guide expects. **"Who is on the hook if it's examined?"** The adviser is responsible for the return; the practitioner's role should be defined in the engagement letter. ## Questions people also ask ### Does a study need an engineer on the team? The IRS prescribes no qualifications. The guide describes engineering-based studies as generally more reliable and names cost estimating experience and legal knowledge as further criteria. A team without an engineer needs someone with equivalent construction and cost competence and should be able to show it. ### Can the tax adviser prepare the study? Yes, if the adviser has the field, estimating and classification competence. More often the adviser reviews the study and applies it; the roles are separate because the skills are. ### Who signs the report? The engagement lead, identified by name with credentials, experience and expertise, as the IRS guide expects. A report signed by a company name only is missing that element. ### Who is responsible if the study is examined? The adviser is responsible for the return. The practitioner's role in an examination should be defined in the engagement letter, including fees. ### How does a solo practitioner get independent review? Through a peer arrangement with another practitioner, a reviewer engaged for the purpose, or a professional body's review process. What matters is that the reviewer did not do the work. ## Sources - https://www.irs.gov/pub/irs-pdf/p5653.pdf — IRS Publication 5653, Cost Segregation Audit Techniques Guide (Rev. 2-2025): Chapter 4, Principal Elements of a Quality Cost Segregation Study and Report. - https://www.irs.gov/pub/irs-pdf/pcir230.pdf — Treasury Department Circular No. 230: §10.3, §10.22, §10.34, §10.35, §10.37. - https://nbcss.org/standards — NBCSS standards and governance: who decides. ## Related reading - [How to become a cost segregation specialist](/articles/how-to-become-a-cost-segregation-specialist) - [What a cost segregation job involves](/articles/what-a-cost-segregation-job-involves) - [Working with reviewers](/articles/working-with-reviewers) - [When to involve a tax adviser](/articles/when-to-involve-a-tax-adviser) - [Career routes into cost segregation](/articles/career-routes-into-cost-segregation) - [The two ways to join NBCSS](/join) --- Canonical: https://nbcss.org/articles/preparer-roles-in-a-cost-segregation-study Published: 2026-09-25 · Last content change: 2026-09-25 Not professional advice: general educational information from the National Board of Cost Segregation Specialist (NBCSS); not accounting, tax, legal, financial, investment or engineering advice. Verify with a licensed CPA, enrolled agent, attorney or other qualified adviser before acting.