Bihar land-record reference labels¶

This stage treats the official Bihar land record as the preferred transcription for an already-linked elector. The source is unusually valuable because a landholder has a strong incentive to have the registered name written correctly. It is therefore Upnaam’s highest-quality Bihar reference source.

The source still contains a full name, not an explicit surname field. The target is consequently precise: the final eligible token in the official land-side name under Upnaam’s declared Bihar rule. It is a reference surname for name-resolution research, not a claim about a legal or hereditary surname.

Source tables¶

The local Shekhpura land-owner table contains 127,449 unique accounts and the local electoral table contains 467,304 rows. The upstream pilot retained 4,387 unique one-to-one account/elector links after exact comparison of normalized block, complete person name, and complete relative name, followed by an electoral-age restriction of 18–110. That is 3.4% of land accounts.

Actual linked strings include:

Land name	Land relative	Roll name	Roll relative
`मथुरा साव`	`रामेश्‍वर साव`	`मथुरा साव`	`रामेश्वर साव`
`शंकर पासवान`	`अधिक पासवान`	`शंकर पासवान`	`अधिक पासवान`
`युगेश्‍वर यादव`	`रामखेलावन यादव`	`युगेश्वर यादव`	`रामखेलावन यादव`

The frozen link artifact has one row per land account and unique link_id, roll_id, and external_id. It reports 1,533 female, 2,845 male, and 9 unknown-sex roll rows. The source snapshots do not encode a collection date in the linked artifact; this remains an open provenance question.

Join contract¶

Upnaam does not rebuild or broaden the person linkage.

LEFT    accepted Bihar land links       key: link_id       unique: 4,387/4,387
RIGHT   same row's land transcription   key: external_id   unique: 4,387/4,387
ROLL    recovered electoral row         key: roll_id       unique: 4,387/4,387
CARD    1:1
OUTPUT  exactly 4,387 rows

The upstream comparison normalizer removed zero-width marks, brackets, and a list of honorific strings before exact matching. It removed those strings wherever they occurred, not just as prefixes. Upnaam does not reuse that normalizer for surname selection. It applies normalization-v1 and the public final-token rule to the untouched land and roll names.

A proposed independent linkage withholding the elector’s own name was tested and rejected. Exact block, full relative name, relation type, and land mouza-to-roll-location agreement produced 2,696 nominally unique one-to-one pairs, but only 289 (10.7%) agreed on the held-out full name. Relatives are shared across siblings and do not identify the elector. Those pairs are not labels and are not written by the pipeline.

Label rule and recode ledger¶

The source-to-reference decisions are:

Land result	Roll result	Reference status	Reason
Final token selected	Same normalized final token	`accepted`	`land_and_roll_surname_agree`
Final token selected	Roll abstains	`accepted`	`land_record_adds_reference_surname`
Final token selected	Different roll final token	`excluded`	`land_roll_position_conflict`
Land abstains	Any	`abstained`	`land_surname_unresolved`

The mandatory source-to-derived crosstab is:

Land positional result	Roll selected	Roll single-token abstention
Selected	4,366	1
Single-token abstention	0	20

No title or sex-marker list is used after token selection. Devi, Kumari, Rani, Singh, Kumar, and similar strings remain eligible when they occupy the final position. The one selected-token conflict is preserved rather than resolved by intuition: roll प्रेमलता कुमारी, land कुमारी प्रेमलता.

Output dictionary¶

One restricted output row represents one accepted upstream land-account to elector link, whether or not it yields a reference label.

Field	Type	Universe and missingness	Meaning and provenance
`link_id`	string	All 4,387; complete and unique	Standardized accepted-link ID
`roll_id`	string	All; complete and unique	Electoral identifier recovered upstream
`land_account_no`	string	All; complete and unique	Official land account number
`roll_name_raw`	string	All; complete	Untouched electoral name
`land_name_raw`	string	All; complete	Untouched official landholder name
`roll_surname_raw`	string	4,366 selected; 21 null	Exact roll token under the Bihar final-token rule
`roll_surname_source_normalized`	string	Same universe as roll raw token	`normalization-v1` comparison form
`land_surname_raw`	string	4,367 selected; 20 null	Exact land token under the Bihar final-token rule
`land_surname_source_normalized`	string	Same universe as land raw token	`normalization-v1` comparison form
`reference_surname_raw`	string	4,366 accepted; 21 null	Preferred land-side token after conflict handling
`reference_surname_source_normalized`	string	Same universe as reference raw token	Normalized reference label
`reference_label_status`	string	All; complete	`accepted`, `abstained`, or `excluded`
`reference_label_reason`	string	All; complete	Stable rule outcome listed above
`reference_provenance`	string	Accepted labels only	`land_record`
`reference_position`	string	Accepted labels only	`last`
`relation_type`	string	8 null in source	Roll relationship field; not used to select surname
`sex`	string	9 null in source	Standardized roll sex; used only for coverage audit
`full_name_normalized_agreement`	boolean	All; complete	Exact comparison under `normalization-v1`
`linkage_basis`	string	All; complete	Frozen upstream one-to-one linkage design
`normalization_revision`	string	All; complete	`normalization-v1`
`reference_revision`	string	All; complete	`bihar-land-reference-v1`

The restricted artifact is typed Parquet. Only aggregate diagnostics are committed publicly.

First run¶

Outcome	Rows
Accepted reference labels	4,366
Land and roll final token agree	4,365
Land record adds a label after roll abstention	1
Land-side positional abstention	20
Excluded positional conflict	1
Distinct normalized reference surnames	78

The land-added case is roll श्री देवी and official land name कुमारी देवी, which supplies reference token देवी. The 64 accepted raw-token differences are mostly Unicode formatting distinctions such as सिन्हा/सिन्‍हा; their normalization-v1 forms agree.

Run locally with:

upnaam labels-bihar-land data/derived/links/bihar_land.parquet \
  data/derived/reference/bihar_land_labels.parquet \
  --audit data/audit/bihar_land_reference.json \
  --summary data/audit/bihar_land_reference.csv \
  --manifest data/manifests/bihar_land_reference.json

The manifest fingerprints the source links and every requested output and records the linkage, normalization, reference-label, and surname-rule revisions. No cloud query, fuzzy linkage, LLM, or manual surname annotation is used.