1.Calculation method
- Evaluator
- At the developer's request, generative AI (Claude Code) calculated the costs from public market rates and work hours.
- Basis
- The calculation is based on public statistics and market rates (an approximate functional size method, productivity, phase ratios, unit rates, and reduction rates). Each value used has a source, and values without one are marked as assumptions. The in-house cost is also calculated with public statistical rates, not actual salaries.
- As of
- Based on the work hours and structural figures recorded as of , calculated on .
- Note
- This is not an assessment by a third-party organization. It covers two perspectives, technical and market, that the project overview slides do not.
This report compares estimates for developing a system equivalent to Matsuba with external teams against the actual development by one developer who used generative AI (Claude Code) in every phase. The external side has three scenarios, a contract development company, freelancers, and an in-house SaaS company, and together with the in-house (actual) scenario, the four scenarios are shown under two conditions each: without generative AI and with generative AI.
The estimating method differs by scenario. For the three external scenarios, the functional size (an indicative function point count) is derived from the database structure at the reference point and divided by the productivity in public statistics to estimate the total effort, which is then allocated to requirements definition, design through integration test, and system test using the phase ratio in public statistics. The design-through-integration-test portion is split into the five phases of foundation, database, backend, frontend, and cloud in proportion to the actual hours of those phases. The in-house (actual) scenario uses the recorded work hours, and its without-AI figures are not observed values but estimates back-calculated from the actual hours using the per-phase reduction rates.
The three external scenarios share the same effort, duration, headcount, and role allocation; the only difference is the source of the unit rates. Duration follows the standard duration formula (a coefficient multiplied by the cube root of person-months), and headcount is the average number of people working at once, person-months divided by duration.
All unit rates are aligned to before-tax values; where a source gives a range the median is used, for statistics the average across all company sizes and both sexes is used, and fractions of a yen are rounded. Hours per person-month follow the definition of a public institution, and the monthly actual hours of the information and communications industry in public statistics were confirmed to be close to it[1][2]. Generative AI subscriptions are counted at list price only for the with-AI condition of the in-house (actual) scenario and are not added to the external scenarios (adding them would raise the external costs, so leaving them out is the conservative choice).
The indicative function point count is a rough estimate based only on the number of data groups, and the productivity in public statistics reflects contract development before generative AI. The limits of these assumptions are summarized in the note in the appendix.
| Scenario | Who and team | Phase model | Source of unit rates |
|---|---|---|---|
| Contract development company | The whole project is outsourced to a development company with the roles of project manager, architect, engineer, infrastructure engineer, QA engineer, and designer | Standard phases (requirements definition through system test) | Industry association survey of outsourcing rates[3] |
| Freelancers | Self-employed engineers are assembled by job type with the same division of roles | The same standard phases | Published statistics and articles of staffing services[4][5][6] |
| In-house SaaS company | A company with a product development team develops with its own employees | The same standard phases | Annual pay by job type and the overhead rate from public statistics[7][8] |
| In-house (actual) | One developer handled everything from requirements analysis to deployment, using generative AI (Claude Code) in every phase | Recorded work hours (measured) | Hourly rate derived from the same public statistics on annual pay and the overhead rate[7][8] |
The values and sources used in the calculation are listed in the following table.
Assumptions used in the calculation (values and sources)
| Item | Value | Source |
|---|---|---|
| Exchange rate (per US dollar) | ¥159 | [9] |
| Development period | 4.1 months (2026-05-15 to 2026-09-17) | Work hours record |
| Hours per person-monthDefinition used by a public institution (8 hours per day × 20 days per month). The monthly actual hours of regular workers in the information and communications industry in public statistics are close to this value. | 160 hours | [1] |
| Days per month (duration conversion)365 ÷ 12 | 30.4 days | Assumption (no source) |
| Function points per internal logical fileWeight in the NESMA indicative method, which derives functional size only from the numbers of internal logical files and external interface files in the data model; the source notes that deviations of up to about 50% are possible. | 35 FP | [10] |
| Function points per external interface fileWeight in the same method (per external interface file). | 15 FP | [10] |
| FP productivity (median, new development)Median FP productivity for new development from a public institution's analysis data collection (2022 edition; fiscal 2016 to 2021 data; quartiles 0.040 to 0.285 FP per person-hour). Effort covers basic design through system test and includes project management. The data reflects contract development before generative AI, and the source notes that the number of cases for this period is small. The median across all years is 0.094 FP per person-hour. | 0.151 FP per person-hour | [11] |
| Effort share of requirements definitionEffort ratio by phase from an industry association survey (2025 edition): requirements definition : design through integration test : system test = 15 : 60 : 25. The source presents this ratio rounded to multiples of 5; its figure shows 13 : 61 : 26. | 15% | [3] |
| Effort share of design through integration testSame source and ratio. | 60% | [3] |
| Effort share of system testSame source and ratio. | 25% | [3] |
| Additional share for project managementNot added, because the effort in the productivity source includes project management within each phase. The phase-ratio source does not state how project management is treated. | 0% | [11] |
| Standard duration coefficient (applied to the cube root of person-months)Coefficient of the standard duration regression in an industry association survey (2025 edition): duration = 3.23 × cube root of person-months, rounded to one decimal place. | 3.2 | [3] |
| Overhead rate (total labor cost ÷ cash wages)Total labor cost ÷ cash wages for the information and communications industry from public statistics (2021 survey). It covers statutory and non-statutory welfare, retirement benefits, training, and recruiting costs, but not office, equipment, or administrative overhead. The reference period is calendar 2020 (fiscal 2019 for companies that report by fiscal year), and this is the latest survey of labor costs. | 1.24 | [8] |
2.Size and effort estimate
- Screens
- 68
- API endpoints
- 375
- Database tables
- 61
- Logical files
- 17
- Work hours
- 727hours
as of 2026-09-17
The functional size was derived from the database structure at the reference point using the NESMA indicative method. The number of user-recognizable data groups (logical files) is 17, and the number of data groups maintained by external systems and only referenced by this system (external interface files) is 1; multiplying the former by 35 FP and the latter by 15 FP gives a functional size of 610 FP.
Dividing this by the productivity for new development in public statistics, 0.151 FP per person-hour, gives a total effort without generative AI of 4,040 hours. Allocating this to the phases using the phase ratio in public statistics leaves the total unchanged: the external effort is 4,040 hours (equivalent to 25.3 person-months), and with generative AI, applying the per-phase reduction rates gives 3,431 hours.
The in-house (actual) effort is the 727 hours in the work hours record, and the development period is 4.1 months. The without-AI figure is back-calculated phase by phase from the actual hours using the per-phase reduction rates, giving 885 hours (the reduction rate weighted by the actual hours averages 17.1%, and applying this average once gives a slightly different total). Deriving effort from lines of code with public productivity statistics is not used, because the lines of code generated by generative AI cannot be compared with statistics of handwritten code.
Effort per phase (hours). In-house: actual and the without-AI conversion; external: estimated from size (shared by the three scenarios)
| Phase | Without generative AI | With generative AI | Derivation | ||
|---|---|---|---|---|---|
| In-house | External | In-house Actual | External | ||
| Requirements | 116.5 | 606.0 | 109.5 | 569.6 | Ratio (requirements) |
| Foundation | 105.7 | 423.9 | 83.5 | 334.8 | Ratio (design to integration) |
| Database | 18.4 | 73.6 | 14.5 | 58.1 | Ratio (design to integration) |
| Backend | 220.3 | 883.2 | 174.0 | 697.8 | Ratio (design to integration) |
| Frontend | 201.3 | 807.1 | 159.0 | 637.6 | Ratio (design to integration) |
| Cloud environment | 48.9 | 236.0 | 46.5 | 224.2 | Ratio (design to integration) |
| Testing | 70.6 | 1,009.9 | 63.5 | 908.9 | Ratio (system test) |
| Deployment and operations | 8.0 | — | 8.0 | — | Included in other phases |
| Documentation | 90.0 | — | 63.0 | — | Included in other phases |
| Management | 5.5 | — | 5.5 | — | Included in other phases |
| Total | 885.1 | 4,039.7 | 727.0 | 3,431.1 | |
| In person-months (160 hours per person-month) | 5.5 | 25.3 | 4.5 | 21.4 | |
Hours are rounded per phase, so totals may differ by a few hours from the sums of the breakdown quantities. The design-to-integration ratio is split across the five phases in proportion to the actual hours.
3.Conclusion
Conclusion per scenario
Contract development company
- Without generative AI
- ¥24.2M 3 people, 9.4 months
- With generative AI
- ¥20.6M 2 people, 8.9 months
Freelancers
- Without generative AI
- ¥19.0M 3 people, 9.4 months
- With generative AI
- ¥16.2M 2 people, 8.9 months
In-house SaaS company
- Without generative AI
- ¥17.2M 3 people, 9.4 months
- With generative AI
- ¥14.6M 2 people, 8.9 months
Because the standard phase model is applied, the effort may come out higher than a product team's actual practice.
In-house (actual)
- Without generative AI
- ¥3.8M 1 person, 5.0 months
- With generative AI
- ¥3.3M Actual 1 person, 4.1 months
The without-AI figures are not observed values but estimates back-calculated from the actual hours using the per-phase reduction rates.
Cost, headcount, duration, and ratio to actual of the four scenarios (without / with generative AI)
| Scenario | Condition | Cost | Headcount (avg.) | Duration (months) | Difference from actual | Ratio to actual |
|---|---|---|---|---|---|---|
| Contract development company | Without generative AI | ¥24.2M | 3 | 9.4 | +¥20.9M | 7.3× |
| With generative AI | ¥20.6M | 2 | 8.9 | +¥17.3M | 6.2× | |
| Freelancers | Without generative AI | ¥19.0M | 3 | 9.4 | +¥15.7M | 5.7× |
| With generative AI | ¥16.2M | 2 | 8.9 | +¥12.8M | 4.9× | |
| In-house SaaS company | Without generative AI | ¥17.2M | 3 | 9.4 | +¥13.8M | 5.2× |
| With generative AI | ¥14.6M | 2 | 8.9 | +¥11.3M | 4.4× | |
| In-house (actual) | Without generative AI | ¥3.8M | 1 | 5.0 | +¥0.5M | 1.1× |
| With generative AI Actual | ¥3.3M | 1 | 4.1 | — | — |
Headcount is the average number of people working at once (person-months divided by duration, rounded). Involvement varies by role.
Without generative AI, the cost of the contract development company is 7.3× the actual cost. With generative AI, it is 6.2× the actual cost. Even the lowest of the external scenarios, the in-house SaaS company with generative AI, is 4.4× the actual cost. The costs of the freelancers and the in-house SaaS company apply different unit rates to the same effort, and the only difference among the three external scenarios is the source of the unit rates.
Most of the difference comes from the estimating method. The external effort is an estimate that applies the industry's median productivity to the functional size. That productivity reflects contract development by teams before generative AI and includes coordination, documentation, and review. The in-house figure is the measured work hours of one developer, so the assumptions and the team differ. The rest of the difference comes from the source of the unit rates (outsourcing rates, staffing service rates, and annual pay from public statistics) and from the reduction rates of generative AI. The in-house SaaS company uses the same public statistics on annual pay as the in-house scenario, so its rate difference is small. The in-house cost with generative AI is the labor cost of the actual hours plus the generative AI subscriptions, and the difference from the without-AI figure is the labor cost of the difference between the back-calculated hours and the actual hours, minus the subscriptions.
4.Cost by scenario
4.1Contract development company
This scenario outsources the whole project to a development company with the roles of project manager, architect, engineer, infrastructure engineer, QA engineer, and designer. It includes requirements definition through system test and project management, and excludes the client's preparation of requirements, acceptance testing, maintenance, and cloud usage fees. In general, the back-and-forth of contracts and estimates and the handling of specification changes affect effort and cost. The duration is 9.4 months (an average headcount of 3 people) without generative AI and 8.9 months (an average headcount of 2 people) with generative AI.
Breakdown for Contract development company (without / with generative AI)
Unit rates in yen per person-month (before tax)
| Phase | Role | Unit rate | Without generative AI | With generative AI | ||
|---|---|---|---|---|---|---|
| Quantity (person-months) | Subtotal | Quantity (person-months) | Subtotal | |||
| Requirements | Architect | ¥960,000 [3] | 2.27 | ¥2,179,200 | 2.14 | ¥2,054,400 |
| Project manager | ¥960,000 [3] | 1.51 | ¥1,449,600 | 1.42 | ¥1,363,200 | |
| Foundation | Architect | ¥960,000 [3] | 2.65 | ¥2,544,000 | 2.09 | ¥2,006,400 |
| Database | Engineer | ¥960,000 [3] | 0.46 | ¥441,600 | 0.36 | ¥345,600 |
| Backend | Engineer | ¥960,000 [3] | 5.52 | ¥5,299,200 | 4.36 | ¥4,185,600 |
| Frontend | Engineer | ¥960,000 [3] | 4.04 | ¥3,878,400 | 3.19 | ¥3,062,400 |
| Designer | ¥960,000 [3] | 1.01 | ¥969,600 | 0.80 | ¥768,000 | |
| Cloud environment | Infrastructure engineer | ¥960,000 [3] | 1.48 | ¥1,420,800 | 1.40 | ¥1,344,000 |
| Testing | QA engineer | ¥960,000 [3] | 4.42 | ¥4,243,200 | 3.98 | ¥3,820,800 |
| Engineer | ¥960,000 [3] | 1.89 | ¥1,814,400 | 1.70 | ¥1,632,000 | |
| Total | 25.25 | ¥24,240,000 | 21.44 | ¥20,582,400 | ||
4.2Freelancers
This scenario assembles self-employed engineers by job type with the same division of roles as the contract development company. The scope is the same, and project management is handled by the project manager role within the team. The unit rates are averages by job type from published statistics of staffing services, with the QA engineer and designer rates taken as the medians of ranges in articles. The sources do not state whether the listed figures are the freelancer's receipts or the client's payments. In general, dependence on specific individuals and continuity are the concerns.
Breakdown for Freelancers (without / with generative AI)
Unit rates in yen per person-month (before tax)
| Phase | Role | Unit rate | Without generative AI | With generative AI | ||
|---|---|---|---|---|---|---|
| Quantity (person-months) | Subtotal | Quantity (person-months) | Subtotal | |||
| Requirements | Architect | ¥900,000 [4] | 2.27 | ¥2,043,000 | 2.14 | ¥1,926,000 |
| Project manager | ¥820,000 [4] | 1.51 | ¥1,238,200 | 1.42 | ¥1,164,400 | |
| Foundation | Architect | ¥900,000 [4] | 2.65 | ¥2,385,000 | 2.09 | ¥1,881,000 |
| Database | Engineer | ¥710,000 [4] | 0.46 | ¥326,600 | 0.36 | ¥255,600 |
| Backend | Engineer | ¥710,000 [4] | 5.52 | ¥3,919,200 | 4.36 | ¥3,095,600 |
| Frontend | Engineer | ¥710,000 [4] | 4.04 | ¥2,868,400 | 3.19 | ¥2,264,900 |
| Designer | ¥650,000 [6] | 1.01 | ¥656,500 | 0.80 | ¥520,000 | |
| Cloud environment | Infrastructure engineer | ¥680,000 [4] | 1.48 | ¥1,006,400 | 1.40 | ¥952,000 |
| Testing | QA engineer | ¥725,000 [5] | 4.42 | ¥3,204,500 | 3.98 | ¥2,885,500 |
| Engineer | ¥710,000 [4] | 1.89 | ¥1,341,900 | 1.70 | ¥1,207,000 | |
| Total | 25.25 | ¥18,989,700 | 21.44 | ¥16,152,000 | ||
4.3In-house SaaS company
This scenario is a company with a product development team developing with its own employees, mapping the roles of product manager, tech lead, engineers, SRE, QA, and designer onto the same role allocation. The scope is the same, and the range of personnel costs is as described in the note on the overhead rate. Because the standard phase model is applied, the effort may come out higher than a product team's actual practice.
Breakdown for In-house SaaS company (without / with generative AI)
Unit rates in yen per person-month (before tax)
| Phase | Role | Unit rate | Without generative AI | With generative AI | ||
|---|---|---|---|---|---|---|
| Quantity (person-months) | Subtotal | Quantity (person-months) | Subtotal | |||
| Requirements | Architect | ¥918,675 [7] | 2.27 | ¥2,085,392 | 2.14 | ¥1,965,965 |
| Project manager | ¥918,675 [7] | 1.51 | ¥1,387,199 | 1.42 | ¥1,304,519 | |
| Foundation | Architect | ¥918,675 [7] | 2.65 | ¥2,434,489 | 2.09 | ¥1,920,031 |
| Database | Engineer | ¥597,752 [7] | 0.46 | ¥274,966 | 0.36 | ¥215,191 |
| Backend | Engineer | ¥597,752 [7] | 5.52 | ¥3,299,591 | 4.36 | ¥2,606,199 |
| Frontend | Engineer | ¥597,752 [7] | 4.04 | ¥2,414,918 | 3.19 | ¥1,906,829 |
| Designer | ¥557,566 [7] | 1.01 | ¥563,142 | 0.80 | ¥446,053 | |
| Cloud environment | Infrastructure engineer | ¥630,085 [7] | 1.48 | ¥932,526 | 1.40 | ¥882,119 |
| Testing | QA engineer | ¥597,752 [7] | 4.42 | ¥2,642,064 | 3.98 | ¥2,379,053 |
| Engineer | ¥597,752 [7] | 1.89 | ¥1,129,751 | 1.70 | ¥1,016,178 | |
| Total | 25.25 | ¥17,164,038 | 21.44 | ¥14,642,137 | ||
Because the standard phase model is applied, the effort may come out higher than a product team's actual practice.
4.4In-house (actual)
This is the record of one developer who handled everything from requirements analysis to deployment, using generative AI (Claude Code) in every phase. It includes all items in the work hours record and the generative AI subscriptions, and excludes equipment, cloud usage fees, and maintenance. The generative AI subscriptions are the list price × usage period of each seat (account) that the same developer used in parallel. The unit rates are hourly rates derived from annual pay by job type and the overhead rate in public statistics, not actual salaries. The without-AI figures are not observed values but estimates back-calculated from the actual hours using the per-phase reduction rates, and because the conservative end of the sources is used, they are on the lower side.
Breakdown for In-house (actual) (without / with generative AI)
Unit rates in yen per hour (before tax)
| Phase | Role | Unit rate | Without generative AI | With generative AI Actual | ||
|---|---|---|---|---|---|---|
| Quantity (hours) | Subtotal | Quantity (hours) | Subtotal | |||
| Requirements | Architect | ¥5,742 [7] | 116.5 | ¥668,943 | 109.5 | ¥628,749 |
| Foundation | Architect | ¥5,742 [7] | 105.7 | ¥606,929 | 83.5 | ¥479,457 |
| Database | Engineer | ¥3,736 [7] | 18.4 | ¥68,742 | 14.5 | ¥54,172 |
| Backend | Engineer | ¥3,736 [7] | 220.3 | ¥823,041 | 174.0 | ¥650,064 |
| Frontend | Engineer | ¥3,736 [7] | 201.3 | ¥752,057 | 159.0 | ¥594,024 |
| Cloud environment | Infrastructure engineer | ¥3,938 [7] | 48.9 | ¥192,568 | 46.5 | ¥183,117 |
| Testing | Engineer | ¥3,736 [7] | 70.6 | ¥263,762 | 63.5 | ¥237,236 |
| Deployment and operations | Infrastructure engineer | ¥3,938 [7] | 8.0 | ¥31,504 | 8.0 | ¥31,504 |
| Documentation | Engineer | ¥3,736 [7] | 90.0 | ¥336,240 | 63.0 | ¥235,368 |
| Management | Project manager | ¥5,742 [7] | 5.5 | ¥31,581 | 5.5 | ¥31,581 |
| Generative AI subscriptions (list price × period) | Claude Max 5x (seat A) | $100 [12] | — | — | 1.4 months | ¥22,260 |
| Claude Max 20x (seat A) | $200 [12] | — | — | 2.8 months | ¥89,040 | |
| Claude Max 20x (seat B) | $200 [12] | — | — | 1.6 months | ¥50,880 | |
| Claude Max 20x (seat C) | $200 [12] | — | — | 1.0 months | ¥31,800 | |
| Total | 885.2 | ¥3,775,367 | 727.0 | ¥3,319,252 | ||
The without-AI figures are not observed values but estimates back-calculated from the actual hours using the per-phase reduction rates.
- Claude Max 5x (seat A): List price. The source article does not state tax treatment, so it is treated as before tax. Billed monthly.
- Claude Max 20x (seat A): List price. The source article does not state tax treatment, so it is treated as before tax. Billed monthly.
- Claude Max 20x (seat B): List price. The source article does not state tax treatment, so it is treated as before tax. Billed monthly.
- Claude Max 20x (seat C): List price. The source article does not state tax treatment, so it is treated as before tax. Billed monthly.
5.Appendix
5.1Basis of unit rates
The unit rates by scenario and role and their sources are as follows. The contract development company's rate is the weighted average outsourcing rate for scratch development from an industry association survey; it reflects user companies' outsourcing records and is not by job type, so the role column describes the team composition. The freelancer rates are averages by job type from published statistics of staffing services (the QA engineer and designer rates are medians of ranges in articles), and the sources do not state whether the listed figures are the freelancer's receipts or the client's payments. The in-house SaaS company and in-house rates are derived from annual pay by job type in public statistics (the 2025 survey of regular workers, all company sizes, both sexes; a year of regularly paid monthly wages plus annual bonuses and other special payments, before tax), and the in-house rates are not actual salaries. Among the rate sources, only the freelance QA engineer article states that its rates exclude tax; the other industry association and staffing service sources state no tax treatment, so they are treated as before tax.
Unit rates by scenario and role, with sources
| Scenario | Role | Unit rate | Source |
|---|---|---|---|
| Contract development company | All roles | ¥960,000 / person-month | [3] |
| Freelancers | Project manager | ¥820,000 / person-month | [4] |
| Architect | ¥900,000 / person-month | [4] | |
| Engineer | ¥710,000 / person-month | [4] | |
| Infrastructure engineer | ¥680,000 / person-month | [4] | |
| QA engineer | ¥725,000 / person-month | [5] | |
| Designer | ¥650,000 / person-month | [6] | |
| In-house SaaS company | Project manager | ¥918,675 / person-monthannual ¥8,890,400 × 1.24 ÷ 12 | [7] |
| Architect | ¥918,675 / person-monthannual ¥8,890,400 × 1.24 ÷ 12 | [7] | |
| Engineer | ¥597,752 / person-monthannual ¥5,784,700 × 1.24 ÷ 12 | [7] | |
| Infrastructure engineer | ¥630,085 / person-monthannual ¥6,097,600 × 1.24 ÷ 12 | [7] | |
| QA engineer | ¥597,752 / person-monthannual ¥5,784,700 × 1.24 ÷ 12 | [7] | |
| Designer | ¥557,566 / person-monthannual ¥5,395,800 × 1.24 ÷ 12 | [7] | |
| In-house (actual) | Project manager | ¥5,742 / hourannual ¥8,890,400 × 1.24 ÷ (12 × 160 h) | [7] |
| Architect | ¥5,742 / hourannual ¥8,890,400 × 1.24 ÷ (12 × 160 h) | [7] | |
| Engineer | ¥3,736 / hourannual ¥5,784,700 × 1.24 ÷ (12 × 160 h) | [7] | |
| Infrastructure engineer | ¥3,938 / hourannual ¥6,097,600 × 1.24 ÷ (12 × 160 h) | [7] |
- Contract development company, All roles: Value from the 2025 edition of the survey.
- Freelancers, Project manager: Source job title: "project manager" (as of November 2025).
- Freelancers, Architect: The source lists no IT architect, so the "IT consultant" figure is used (as of November 2025).
- Freelancers, Engineer: Source job title: "system engineer". In the same source, programmers are listed at 670,000 yen and front-end engineers at 720,000 yen (as of November 2025).
- Freelancers, Infrastructure engineer: Source job title: "infrastructure engineer" (as of November 2025).
- Freelancers, QA engineer: Median of the range for the test-design tier (observed from published listings as of June to July 2026; the source states that it is not a market-wide average).
- Freelancers, Designer: Median of the rate range for UI designers hired through an agency (the article is dated October 2024; the data point in time is not stated).
- In-house SaaS company, Project manager: Job category: "system consultants and designers".
- In-house SaaS company, Architect: Job category: "system consultants and designers".
- In-house SaaS company, Engineer: Job category: "software developers".
- In-house SaaS company, Infrastructure engineer: Job category: "other information processing and communication engineers".
- In-house SaaS company, QA engineer: Job category: "software developers" (there is no separate QA category, so the same category as engineers is used).
- In-house SaaS company, Designer: Job category: "designers" (the category includes designers outside IT).
- In-house (actual), Project manager: Job category: "system consultants and designers".
- In-house (actual), Architect: Job category: "system consultants and designers".
- In-house (actual), Engineer: Job category: "software developers".
- In-house (actual), Infrastructure engineer: Job category: "other information processing and communication engineers".
5.2Reduction with generative AI
Reduction per phase (published range and adopted value)
| Phase | Published range | Adopted | Source |
|---|---|---|---|
| Requirements | Not measured; estimated | 6% | [13][14] |
| Foundation | 21–45% | 21% | [15][16] |
| Database | 21–45% | 21% | [15][16] |
| Backend | 21–45% | 21% | [15][16] |
| Frontend | 21–45% | 21% | [15][16] |
| Cloud environment | Not measured; estimated | 5% | [17][18] |
| Testing | Not measured; estimated | 10% | [19][20] |
| Deployment and operations | Not measured; estimated | 0% | [21][18] |
| Documentation | 30–38% | 30% | [14][16] |
| Management | Not measured; estimated | 0% | [22][18] |
- Requirements: Not measured; estimated. No study measures this phase as a whole. A knowledge-work experiment (25% less time) and a document-writing experiment (40% less time) apply to the documentation part only. Assuming that understanding, agreement, and decisions do not shrink and that documentation is a quarter of the phase, the value is the conservative knowledge-work figure multiplied by a quarter (0.25 × 0.25, rounded to two decimals).
- Foundation: The code-implementation figures are applied (about a 20% reduction in an enterprise controlled experiment as the lower bound and the code-generation range of a lab experiment within a company, not peer reviewed, as the upper bound). Technology selection and design are not measured.
- Database: Schema design decisions are unlikely to shrink, but migrations and queries are code generation, so the code-implementation figures are applied.
- Backend: The lower bound is an enterprise controlled experiment (about a 20% reduction) and the upper bound is the code-generation range of a lab experiment within a company (not peer reviewed). Large reductions reported for single simple tasks are not included in the upper bound.
- Frontend: There is no front-end-specific measurement, so the code-implementation figures are applied. Visual and accessibility checks remain manual.
- Cloud environment: Not measured; estimated. Infrastructure-code generation scores only about 20% on a benchmark and needs verification loops, and a survey shows that most developers do not plan to use AI for deployment and monitoring, so a small value is used.
- Testing: Not measured; estimated. Test-code generation is effective but its time saving is not measured, and one report found no time difference for debugging. The value applies only to test design and implementation, assuming manual checks and defect investigation do not shrink.
- Deployment and operations: Not measured; estimated. There is no time measurement; a survey associates AI adoption with lower delivery stability and another shows that most developers do not plan to use AI for deployment and monitoring, so zero is used.
- Documentation: The document-writing figures (40% in a controlled experiment and 45 to 50% in a lab experiment within a company, not peer reviewed) measure drafting time. Assuming that review, proofreading, and organizing of published documents do not shrink and that drafting is three quarters of the phase, the range is the experimental values multiplied by three quarters.
- Management: Not measured; estimated. A study reports a shift in the share of activities (less management), but not a time reduction, and management is a small share of one-person development, so zero is used.
Limits of the estimate
- The in-house figures without generative AI are not observed values but counterfactual estimates back-calculated from the actual hours using the per-phase reduction rates. Because the conservative end of the sources is used, the without-AI effort is on the lower side.
- Most of the sources for the reduction rates are controlled experiments from the era of code completion and chat tools; the effect of agent-type tools may be larger, but the studies showing this are observational and use count metrics, so they are not used. For single simple tasks, reductions of about half have been reported[23]. On the other hand, a controlled experiment found that developers familiar with mature, large codebases became slower[24], and its follow-up found only a small and uncertain effect[25]. The effect can be positive or negative depending on skill and environment.
- The indicative function point count is a rough estimate, and the source itself notes that errors of about half are possible. Mapping the database structure to logical files is also an approximation, and because the estimate is based only on the number of data groups, the effort may come out low for systems with many screens and API endpoints. The productivity reflects contract development before generative AI with a wide interquartile range, and the source notes that the number of cases in the most recent period is small. Using the median across all years would make the external effort come out higher. The effort in the productivity source does not include requirements definition, while the phase ratio allocates part of the total effort to requirements definition, so the external effort tends to come out low.
- The standard phase model is applied to all three external scenarios, so freelancers and product teams may come out with more effort than in practice. Because effort, duration, headcount, and allocation are the same, the only difference among the three scenarios is the source of the unit rates. Most of the difference between external and in-house comes from the estimating method, an estimate versus a measurement.
- Deriving effort from lines of code with public productivity statistics is not used, because the lines of code generated by generative AI cannot be compared with statistics of handwritten code.
- The years of the sources for unit rates, annual pay, productivity, and phase ratios are not aligned (they are stated in each table). Tax is unified as before tax, and if the rates listed by staffing services are the freelancer's receipts, the client's payments are higher.
- Generative AI subscriptions are not added to the external scenarios; adding them would raise the external costs.
- There are reports that evaluating and refining generated code takes time and that for complex work the verification load offsets the speed gains[20], so applying the same reduction rates to the external scenarios, where teams would use the tools, is a simplification.
5.3Work hours
Work hours per phase during the development period (the total equals the "work hours" figure)
| Phase | Item | Hours |
|---|---|---|
| Requirements | Requirements analysis | 3.0 |
| Requirements definition (including documents) | 8.5 | |
| Research on similar services | 0.5 | |
| Understanding and specification review | 39.5 | |
| Specification design (including documents) | 58.0 | |
| Subtotal | 109.5 | |
| Foundation | Technology selection | 1.0 |
| Technical research and validation | 6.5 | |
| Foundation design | 22.0 | |
| Foundation development | 28.5 | |
| Environment setup (development) | 25.5 | |
| Subtotal | 83.5 | |
| Database | Database design | 4.0 |
| Database implementation | 10.5 | |
| Subtotal | 14.5 | |
| Backend | Backend design | 12.5 |
| Backend development | 161.5 | |
| Subtotal | 174.0 | |
| Frontend | Visual design | 3.0 |
| Frontend design | 20.0 | |
| Frontend development | 136.0 | |
| Subtotal | 159.0 | |
| Cloud environment | Environment setup (cloud) | 46.5 |
| Testing | Test design and implementation | 12.5 |
| Smoke testing | 36.0 | |
| Bug investigation and fixes | 15.0 | |
| Subtotal | 63.5 | |
| Deployment and operations | Deployment | 8.0 |
| Documentation | Writing manuals | 9.0 |
| Technical documentation | 30.5 | |
| Documents for users | 17.0 | |
| Organizing documents | 6.5 | |
| Subtotal | 63.0 | |
| Management | Meetings | 5.5 |
| Total | 727.0 |
5.4How the figures are counted
- Screens 68
- Number of page.tsx files in the web app's App Router tree, excluding the developer preview screens
- API endpoints 375
- Number of paths in the OpenAPI definition (402 operations by HTTP method)
- Database tables 61
- Number of model declarations in the Prisma schema
- Logical files 17
- Number of user-recognizable data groups among the 61 Prisma models that users reference or maintain through screens or the API (internal logical files for the NESMA indicative function point count). Excludes 44 models of 4 kinds: 3 pure many-to-many join tables, 24 technical helper tables (sessions, tokens, job states, and the like), 6 derived or aggregate-only tables, and 11 dependent tables counted together with their parent
- External interface files 1
- Number of data groups maintained by an external system and only referenced by this system (external interface files for the NESMA indicative function point count): one, the Google Workspace directory (user status). The Google Drive file list, which this system also writes, and operational measurements of the system itself (storage and delivery metrics) are not counted
- Work hours 727 hours
- Sum of the work hours recorded per phase during the development period (27 items including requirements analysis, design, development, testing, and documentation)
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