# How should Seoul salon survival rates be read?

> Read the eligible cohort and observed horizon before comparing a survival percentage with another record.

Use the source’s unit, date and classification to answer the question before interpreting a district difference. A public aggregate does not evaluate a named business or predict an individual outcome.

Written by the Gyeonggi Beauty Network editorial team on October 26, 2026. Canonical address: https://seoulsalonfacts.org/articles/reading-survival.

## Why does Seoul salon survival begin with an opening cohort?

A declared opening cohort fixes who is in the denominator before the selected anniversary is evaluated.

A current active share starts with an accumulated file and asks which rows are active now. Survival starts with a particular opening group and asks whether its records had closed by a later point. The two measures can differ substantially without either arithmetic being wrong. Their populations and time questions are different.

**Different questions about a salon’s history**

| Question | Required group | Relevant output |
| --- | --- | --- |
| How many are active now? | Current normal-operation rows | Snapshot count |
| How many opened in a year? | Permit dates within that year | Opening flow |
| What survived an anniversary? | A coherent opening cohort | Survivors / eligible cohort |
| How long did closed entries last? | Closed rows with coherent dates | A closed-record duration |

## Why are some Seoul salon survival horizons unavailable?

A recent opening cohort may not have enough time for all records to reach the requested horizon.

A full-year cohort contains openings throughout the year. Early openings can reach an anniversary before later ones. Publishing only the observed part as the complete cohort would change the denominator in a way a short percentage label does not reveal. The annual rule waits for the full period and keeps the longer horizon unavailable.

A percentage without the original cohort size hides how many records were observed. Keep numerator and denominator together, especially when a district or source-type filter produces a small group. Do not rank a small filtered group as if it had the same evidential weight as a larger one.

## Why can an empty Seoul closure date not always mean survival?

A closed administrative status with no valid end date is unresolved and stays outside the coherent cohort.

The source can identify that a record is closed without supplying a usable date. Treating the missing date as never closed would convert a known closure into a survivor. The method distinguishes that gap from an active record with no closure date. Dates and status are checked together before any anniversary comparison is attempted.

**Cohort exclusions and unresolved observations**

| Condition | Cohort treatment | Current count treatment |
| --- | --- | --- |
| Closed with no valid closure date | Exclude from coherent denominator | Not a normal-operation row |
| Active with a closure date | Exclude conflicting history | Current state filter is still explicit |
| Horizon not fully observed | Do not calculate that horizon | No effect on current-state definition |
| No eligible cohort | No ratio | Not evidence of no current shops |

## How should Seoul salon cohorts be combined?

Add coherent survivors and eligible cohort sizes separately, then divide only once.

A simple average gives every subgroup equal weight even when their sizes differ. Pooling counts instead keeps the contribution of each eligible record. The combined result still needs the same observed horizon and source conditions for all included groups. A larger number of displayed rows does not resolve incompatible observation periods.

## Which Seoul salon anniversary boundary is used?

A recorded closure must occur after the anniversary for that record to survive the selected horizon.

A closure exactly on the anniversary is therefore excluded from surviving that horizon. The date-addition rule also specifies how leap-day openings are treated. Those choices are not visible in a rounded rate, so they belong in the method. A separately computed check should use the same boundary rather than treating a last-digit difference as evidence of an incorrect source.

A later closure report can revise a previously observed anniversary result. This makes snapshot date part of the method. An older published calculation should retain its date rather than being relabelled as if it had been recomputed from the latest file.

## Does Seoul salon survival predict a new operator’s success?

The record describes historical administrative continuity and does not measure an individual’s future profit or goals.

The source has no complete account of debts, owner changes or reasons for reporting a closure. A permit can remain active while a business experiences very different financial conditions from another active business. Survival is therefore an explicitly defined record-based outcome, not a promise that an entrant will earn an income.

## What makes a Seoul salon survival comparison reproducible?

Retain the source version, exclusions, cohort filter, horizon and both counts used in the ratio.

A later source correction can change an old opening or closure date. The same historical cohort may therefore yield a revised result in a new snapshot. Keeping the query date and checksum allows the revision to be located. No business names or detailed locations are required in the published aggregate to explain those calculation conditions.

If another publication reports survival, compare cohort construction and closure definitions before comparing percentages. “Still registered”, “still trading” and “profitable” are different outcomes. A matching name alone does not establish a matching measure.

## What else do people ask about How should Seoul salon survival rates be read??

### Where can I find Seoul beauty-salon statistics?

Use the Seoul Open Data Plaza beauty-business permit dataset. Permit status describes administrative records and does not establish live opening hours or service quality.

### Does unobserved mean zero survival?

It means the requested horizon is not yet fully observed.

### Are missing end dates repaired?

No date is invented to complete a cohort.

### Are percentages averaged equally?

Combined results use pooled numerators and denominators.

### Is survival a profit rate?

The administrative source does not measure profit.

## What should you read next?

- [Do more Seoul salons mean more competition?](https://seoulsalonfacts.org/articles/counts-and-competition)
- [How can Seoul salon opening seasonality be checked?](https://seoulsalonfacts.org/articles/opening-seasonality)
- [Seoul Salon Openings and Closures](https://seoulsalonfacts.org/statistics/openings-closures)
- [Seoul Beauty Salon Survival Rates](https://seoulsalonfacts.org/statistics/survival-rate)

## Where do these numbers come from?

- [Seoul beauty business permit data](https://data.seoul.go.kr/dataList/OA-16063/S/1/datasetView.do) - Seoul Metropolitan Government
- [Seoul beauty permit metadata and reuse terms](https://www.data.go.kr/data/15094774/fileData.do) - Seoul Metropolitan Government / Public Data Portal
- [Beauty licence eligibility](https://www.easylaw.go.kr/CSP/CnpClsMainBtr.laf?ccfNo=1&cciNo=2&cnpClsNo=1&csmSeq=1009&menuType=cnpcls&popMenu=ov) - Ministry of Government Legislation