Source
https://www.branz.co.nz/pubs/research-reports/er91/ — original source (opens in a new tab; the file is not redistributed)
BRANZ ER91 (2024) — ModelDocs: Transforming Building Consenting Behaviour for Better Housing
BRANZ External Research Report ER91 (LR16305, Prof Anthony Hōete, University of Auckland 6W Research programme, Oct 2024). A data-driven behavioural study of NZ dwelling building-consent processing — it mines the Requests for Information (RFIs) on May-2023 dwelling consents from Auckland and Tauranga councils to show that consenting delay is driven by Sender documentation behaviour, not BCA processing time. Thesis-context governance/housing-supply background;
feeds:[].
Summary
ModelDocs (BRANZ ER91, LR16305) is a University of Auckland study by Professor Anthony Hōete’s 6W Research programme that asks why New Zealand’s building-consent system is slow and how to fix it behaviourally rather than through legislation. It reframes the two parties as “Senders” (those who prepare a consent application — LBPs, architects, engineers) and “Receivers” (the Building Consent Authorities who process it), establishes a behavioural baseline via a national survey (>200 respondents), then runs a three-stage “data deep dive” into the Requests for Information (RFIs) generated during processing of dwelling consents granted by Auckland and Tauranga councils in May 2023. Its central, myth-busting finding is that 86% of RFI items trace to Sender behaviour (66% of them simply missing documentation) and that it is the Sender’s response time, not BCA processing, that creates delay — Auckland took 55 days to grant a consent but only 19 of those were actual processing (inside the 20-day statutory limit), with 36 days spent waiting for the Sender. With ~30 RFI line items per consent and >20,000 dwelling consents in 2023, the report estimates 600,000+ RFI line items a year — “half a million days lost, at a cost of over a $NZ billion.” It recommends non-regulatory “quick wins”: targeting the two clauses (B1 Structure, E2 External Moisture) and the Sender group (LBPs) that generate most missing-doc RFIs. For the thesis this is governance/housing-supply context — the institutional friction any community (including a remote, self-building one) must navigate to put roofs over heads — and a sibling to OT_058 (ER107) and OT_054 (ER81) in the BRANZ housing-systems stream. context: thesis, feeds: [] — background, not an NI calculation input.
Key claims
- claim: "ModelDocs (BRANZ External Research Report LR16305, published October 2024; research dated 30 August 2024) by Professor Anthony Hōete's 6W Research programme at the University of Auckland, funded by the Building Research Levy, investigates the BEHAVIOUR of those who prepare a building consent application ('Senders') and those who process it ('Receivers'), seeking non-regulatory 'quick wins' that 'fast-follow' existing policy. Stated research constraints: 'behavioural, not legislative nor technological, transformation'; 'focused on processing, not inspections or certification'; 'limited to dwelling consents within May 2023'; 'granted by two metropolitan Building Consent Authorities (BCAs), medium-sized Tauranga City Council and the larger Auckland Council.' Method: a national survey (a 'sample of over 200 respondents') to establish a Sender–Receiver behavioural baseline, then a three-stage 'data deep dive' using the RFI (Request for Information) as the indicator of behavioural in/efficiency."
source_location: "§3 Executive Summary, pp.5–6; §4 Background, pp.12–14; §6 Research Methodology, p.17"
- claim: "RFI volume (Key Finding 1): 'On average, the processing of a consent generates 30 RFI Line Items. Each needs a Sender response. As there were more than 20,000 dwelling consents granted in NZ in 2023, this means over 600,000 items would need resolving annually.' Restated: 'In 2023, the 20,177 dwelling consents granted would equate to over 600,000+ RFI line items across the country. That's half a million days lost, at a cost of over a \$NZ billion.' In the deep dive each consent generated 2.3 (TGA) to 2.5 (AKL) RFI letters containing 27 (TGA) and 30 (AKL) sub-line items each; combined, the two BCAs averaged 2.4 RFIs and 28.5 SLIs per consent."
source_location: "§13 Key Findings #1, p.82 (Fig 11.8); §3 Exec Summary, pp.5–6; §11 Data Deep Dive, p.49 (2.4 RFIs / 28.5 SLIs)"
- claim: "Delay is a Sender phenomenon (Key Finding 2): 'It is the Sender's response time that creates consenting delays' — not BCA processing. For Auckland the average time to grant was 55 days, of which the council waited 36 days for the Sender and its actual processing time of 19 days was LESS than the 20-day statutory limit; for Tauranga 39.7 days total (18.4 on hold, 21.3 processing). Median analysis (chosen over the average because outliers skew it): of TGA's 81 May-2023 consents only C2/C3 complexity exceeded a 20-day median (R1 17, R2 20, R3 20, C1 18, C2 28, C3 44 days); of Auckland's 190 consents only R3 exceeded it (R1 16, R2 17, R3 23, C1 11, C2 18, C3 18 days). 'ModelDocs found scant evidence of widespread or excessive delays due to the time BCAs spent on processing' — across n=160 tracked consents 'little evidence of systemic delays or the mythical stop-clock' was found, and Sender 'consenting delay' disgruntlement 'appears to be misplaced anecdotal behaviour.'"
source_location: "§13 Key Findings #2, p.82 (Fig 11.10); §3 Exec Summary, p.6; §11 Data Deep Dive, pp.50–51 (Figs 11.9–11.10)"
- claim: "Responsibility split (Key Finding 4): '86% of RFI items are related to Sender behaviour and 14% to Receiver behaviour.' Within the code-clause issues '66% relate to missing documents', with the remainder 'incorrect' (10%), 'correct' (9%), 'obscured' (10%) and 'coordination' (5%). The executive-summary breakdown of the Sender 86%: missing documentation 66%, incorrect docs 10%, coordination issues (e.g. between Architect and Engineer) 5%, and obscured docs a shared Sender/Receiver responsibility at 5%."
source_location: "§13 Key Findings #4, p.82 (Fig 11.46); §3 Exec Summary, p.6"
- claim: "RFI types and the two decisive clauses (Key Findings 3 & 5): '20-25% related to general and documentation issues, while 75-80% related to NZ Building Code clauses' (Tauranga 19.9% Gen&Doc / 80.1% Code; Auckland 25.4% / 74.6%). 'The majority of the Missing documentation related to New Zealand Building Code clauses B1 Structure (31%) and E2 Weathertightness (19%)' — B1 the most common (TGA 31% / AKL 32%), E2 External Moisture second (TGA 25% / AKL 19%). 'If the research targeted these two code clauses, then it could potentially resolve over half of the line items.'"
source_location: "§13 Key Findings #3 & #5, p.82 (Figs 11.11–11.16); §3 Exec Summary, p.7"
- claim: "Sender profile and the 'wins' (Key Finding 6 + Recommendations): 'LBPs (Design Class) dominate housing consent applications, representing 87% of Tauranga and 70% of Auckland applications', with architects the second-largest profile at **8% of Tauranga and 25% of Auckland** and engineers 3% in both cities (Figs 11.23–11.24; report body p.35, 'Architects were the second largest profile, representing 8% of TGA and 25% of AKL'). ⚠ Source-internal transposition: the report's own Executive Summary point 6 (p.9) states 'Architects represented 25% and 8% of Senders respectively' — that ordering is transposed against the 87%-TGA/70%-AKL order it sets in the same sentence; the body text and Figs 11.23–11.24 (Tauranga architect 8%, Auckland architect 25%) are authoritative. 'R1-R3 dwellings represent 90% of consents', so advice 'should have an R1-R3 dwelling focus.' The recommendations are framed as cumulative wins: a '43% win' from LBP missing-docs behaviour (of the 66% missing-info line items, 65% were LBP responsibility), a '20% win' from architects (31% responsibility), and a '14% win' from Receiver behaviour (RFIs that need not have been sent because the docs were originally correct 9% or present-but-obscured 5%)."
source_location: "§13 Key Findings #6, p.82 (Figs 11.23–11.24 — architect shares 8% TGA / 25% AKL); §11 Sender profile (Figs 11.23–11.24); §14 Recommendations, p.83 (Figs 11.46, 11.48); §3 Exec Summary, pp.7, 9 (Exec-Summary point 6 transposes the architect shares as '25% and 8%')"
- claim: "Consenting volume, intensification and geography: 'In 2023, NZ consented 37,329 dwelling units over 20,177 consents (Stats NZ). That averages out as 1.85 dwellings per consent (1.85 : 1). This is a 35% increase in dwelling units per consent since 2018 (1.37 : 1).' 'Tauranga TGA (2%) and Auckland AKL (42%) represent 44% of those 20,177 dwelling units consented in 2023.' Townhouses rose from 19% of all dwelling units consented in 2018 to 45% by 2023 (Fig 9.1)."
source_location: "§3 Exec Summary, p.5; §4 Background, p.12; §3 Exec Summary, p.7 (townhouses 19%→45%, Fig 9.1)"
- claim: "Processing is a small slice of the build timeline. Days to key milestones from the date a building consent is granted (Stats NZ, April 2024): first inspection 163 calendar days, final inspection 533 calendar days, code compliance certification 569 calendar days. **BCA processing alone** adds only ~5% of the time to final inspection (TGA 21 working days = 29 calendar days; AKL 19 working days = 28 calendar days — inside the 20-working-day statutory clock). It is only **once the wait for the Sender's response is added in** (the report's 'Council processing plus awaiting Sender response' line) that the share rises to ~11% for Tauranga (40 days = 56 calendar days) and ~14% for Auckland (55 days = 77 calendar days) — so the 14% / 55-day figure is total processing-plus-Sender-wait, NOT BCA processing time."
source_location: "§3 Exec Summary, p.6 ('How critical is the consenting timeframe within the wider timeframe of building a house?')"
- claim: "Housing-affordability and build-cost framing (ER91 citing external sources): 'Over the last 20 years, New Zealand has experienced faster growth in real house prices than any other OECD country' (NZ Infrastructure Commission Research Insights, March 2022); the BNZ Chief Economist estimated NZ needs 45,000–50,000 new homes in 2024, and Auckland needs 320,000 new dwellings by 2050 (Auckland Plan 2050). MBIE calculated the 2022 per-square-metre cost to build a home (excl. external works) at NZ \$2,591 versus \$1,742 across the Tasman — a cost that has 'increased by 41% since 2019 and today is, reportedly, 50% more expensive than in Australia' (NBR, 15 Feb 2024); group house builders 'report build costs today at between \$3,300 - \$3,800.' New Zealand has 68 Building Consent Authorities and 67 territorial authorities (13 city councils, 53 district councils and the Chatham Islands Council)."
source_location: "§3 Exec Summary, p.5; §4 Background, pp.12–13 (Fig 4.1); §2 Glossary, p.4 (67 TAs); §4 Background, p.12 (68 BCAs)"
- claim: "Systemic/governance diagnosis (drawing on the December 2022 MBIE 'Review of the Building Consent System: Issues' and February 2024 'Options'): roles and responsibilities across the system are 'only partially understood and accepted'; capability and capacity constraints are undermining it; there is 'a lack of system agility as all consent applications currently go through a \"one size fits all\" process, regardless of risk, complexity or type. A house alteration, for example, is allocated the same 20-workday processing time frame as a high-rise residential tower' (Building Act 2004 s48/s49); 'variability and unpredictability within and between BCAs' fragment implementation; and 'the current consent system is not sufficiently responsive to the building needs and aspirations of Māori' — a Centre of Excellence for Māori-led construction projects 'received the most support.' On liability: under 'joint and several liability' the Council is 'ultimately the \"last man standing\" and assumes all the risk and little of the developer gain', and Producer Statements 'currently have no legal status in the Building Act.'"
source_location: "§4 Background, pp.13–14 (MBIE Review Issues Dec 2022 & Options Feb 2024)"Key thesis insights
- Consenting is a governance bottleneck to housing supply — but the bottleneck is behavioural, not statutory. ModelDocs uses evidence to bust the popular “BCA delay” narrative: 86% of RFIs trace to Sender documentation behaviour (66% simply missing docs), and BCA processing sits inside the 20-day statutory clock — Auckland’s 55-day figure is 36 days waiting on the Sender plus 19 days processing. For the thesis’s governance argument, this is a clean case of a data-driven diagnosis overturning an anecdotal, politically-charged story about institutional failure. OT_136
- The friction any self-building community must navigate is real and quantified. ~30 RFI line items per consent, concentrated in two Building Code clauses (B1 Structure, E2 External Moisture), across 68 inconsistent BCAs (“69 BCAs, each doing their own thing”). A remote or intentional community that builds its own dwellings inherits this processing overhead — context for the self-sufficiency argument and complementary to the off-grid/alternative-dwelling consenting picture in regulatory_consenting_off_grid_nz, REG_001 and REG_003. OT_136
- Institutional design failure modes. The report names three governance pathologies worth citing: (1) a “one size fits all” 20-workday process that treats a house alteration and a high-rise tower identically (Building Act s48); (2) “joint and several liability” that makes the Council the risk-absorbing “last man standing” as designers/developers “elect to go bust”, driving BCA risk-aversion; and (3) Producer Statements that carry “no legal status in the Building Act”. These are concrete examples of how liability regimes and process rigidity shape institutional behaviour. OT_136
- The Māori-responsiveness gap. The system is “not sufficiently responsive to the building needs and aspirations of Māori”, and a Centre of Excellence for Māori-led construction “received the most support” of the reform options — linking the consenting-governance strand to the Māori-housing thread in OT_051 (MAIHI) and OT_058 (ER107). OT_136
- A non-regulatory theory of change. ModelDocs deliberately seeks “change within the system, not to change the system itself” — behavioural “quick wins” that “fast-follow” existing policy (CPD, checklists, better documentation) rather than legislative reform. As a model of how institutions and their professional communities can shift behaviour without waiting on statute, it is a useful counterpoint for the thesis’s governance/adaptation discussion. OT_136
Research targets
Documents to retrieve
- RT_380 — MBIE, Review of the Building Consent System — the Issues discussion document (December 2022) and the Options paper (February 2024). ER91 responds to both at length (§4 Background, pp.13–14); they are the primary policy documents behind the consenting-reform debate and would let the governance argument be cited at origin rather than via ER91. → thesis (governance / regulation)
Research gaps
- The NZ Infrastructure Commission “Research Insights” (March 2022) on NZ’s OECD-leading real house-price growth, and the ENZ Structural Design Documentation Guidance (cited as forthcoming, aimed at reducing B1 Structure RFIs) are noted in-report as leads, not raised as formal targets — retrieve only if the thesis housing-supply / documentation-standards threads need them at source.
Notes
BRANZ External Research Report ER91 (LR16305; published October 2024, research dated 30 August 2024; ISSN 2423-0839), Professor Anthony Hōete’s 6W Research programme, University of Auckland, funded by the Building Research Levy. 85 pp. Read verbatim via pdftotext -layout — data_quality: verified (every figure traces to the raw; matches the verified sibling ER report OT_058). context: thesis, feeds: [] — building-governance / housing-supply background, not an NI calculation input.
⚠ Attribution, not first-party data. Several headline figures are ER91 citing other bodies: dwelling-consent counts (37,329 units / 20,177 consents), milestone days and the 1.85:1 ratio are Stats NZ; the OECD house-price claim is the NZ Infrastructure Commission (March 2022); the 45,000–50,000 homes figure is the BNZ Chief Economist; per-m² build costs and the “+41% since 2019 / 50% more than Australia” line are MBIE / NBR (15 Feb 2024); the systemic diagnosis is the MBIE Review of the Building Consent System. Attributed inline in the key_claims — verify the attribution wording, not just the number.
⚠ Two source-internal figure notes (verified against the raw at ingest). (1) Architect shares: the Executive Summary point 6 transposes them as “25% and 8% … respectively”, but the report body (p.35) and Figs 11.23–11.24 give 8% Tauranga / 25% Auckland — the corrected figures are used in the Sender-profile key_claim. (2) Timeline share: the AKL “55 days = 77 calendar days = ~14%” figure is total processing-plus-Sender-wait, not BCA processing — Auckland’s BCA processing alone is 19 days (~5%, inside the 20-working-day statutory limit); the key_claim labels the two metrics distinctly.
⚠ Scope. Two BCAs only (Auckland + Tauranga), dwelling consents in May 2023, processing stage only — not inspections or Code Compliance Certification, and explicitly not a legislative or technological study. Do not over-generalise the Auckland/Tauranga percentages to all 68 BCAs; the report itself flags inter-BCA variability as a headline problem.
Sibling to OT_058 (ER107) and OT_054 (ER81) in the BRANZ housing-systems stream; complements the consenting-governance concept page regulatory_consenting_off_grid_nz.
Connections
Links to