@moj-bichard7-developers/bichard7-next-core

Offence matching algorithm

Bichard receives court results and needs to update offences on the PNC with these results. Unfortunately, for unknown reasons, the ID to use on the PNC for updating is not included in the message from the court. This means that we need to work out which offence in the PNC matches which offence in the court result. There are some complications to this, however:

• Offences may be added in the court
• The data for offences coming from the courts may not match those in the PNC
• There may be offences with identical details (date, offence code, etc)
• Offences from the court may be from two separate court cases in the PNC

The original algorithm in Bichard to do this matching was extremely complex. We are aiming to simplify it. The new algorithm tries to match the offences in multiple stages:

1. Try to match all offences exactly in one court case

If there are exact matches (sequence number, offence code, dates) for every offence in a hearing outcome in a single court case, and all offences are matched, then we will accept these as correct matches. e.g.

Hearing Outcome Offences

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88218	2022-07-19		2063
002	TH68143	2022-07-19		4028

PNC Offences

Court Case Number: 22/2041/111111X

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88218	2022-07-19		2063
002	TH68143	2022-07-19		4028

Court Case Number: 22/2041/222222Y

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88218	2022-07-19		2063

Matches

HO Offence	PNC Offence	PNC Court Case
001	001	22/2041/111111X
002	002	22/2041/111111X

2. Try to match all offences exactly across multiple court cases

If there are exact matches (sequence number, offence code, dates) for every offence in a hearing outcome across multiple court cases, and all offences are matched, then we will accept these as correct matches. e.g.

Hearing Outcome Offences

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88334	2022-07-19		2063
002	TH68143	2022-07-19		4028

PNC Offences

Court Case Number: 22/2041/111111X

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88218	2022-07-19		2063
002	TH68143	2022-07-19		4028

Court Case Number: 22/2041/222222Y

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88334	2022-07-19		2063

Matches

HO Offence	PNC Offence	PNC Court Case
001	001	22/2041/222222Y
002	002	22/2041/111111X

3. Try to match again ignoring the sequence numbers but with exact dates, prioritising a single court case with all matches

If there are matches (offence code, dates) for every offence in a hearing outcome in a single court case, and all offences are matched, then we will accept these as correct matches. e.g.

Hearing Outcome Offences

Sequence Number	Offence Code	Start Date	End Date	Result codes
003	RT88218	2022-07-19		2063
004	TH68143	2022-07-19		4028

PNC Offences

Court Case Number: 22/2041/111111X

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88218	2022-07-19		2063
002	TH68143	2022-07-19		4028

Court Case Number: 22/2041/222222Y

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88218	2022-07-19		2063

Matches

HO Offence	PNC Offence	PNC Court Case
003	001	22/2041/111111X
004	002	22/2041/111111X

4. Try to match again ignoring the sequence numbers but with exact dates, acros multiple court cases

If there are matches (offence code, dates) for every offence in a hearing outcome across multiple court cases, and all offences are matched, then we will accept these as correct matches. e.g.

Hearing Outcome Offences

Sequence Number	Offence Code	Start Date	End Date	Result codes
003	RT88334	2022-07-19		2063
004	TH68143	2022-07-19		4028

PNC Offences

Court Case Number: 22/2041/111111X

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88334	2022-07-19		2063
002	TH68143	2022-07-19		4028

Court Case Number: 22/2041/222222Y

Sequence Number	Offence Code	Start Date	End Date	Result codes
001	RT88334	2022-07-19		2063

Matches

HO Offence	PNC Offence	PNC Court Case
003	001	22/2041/222222Y
004	002	22/2041/111111X

Exceptions to raise are:

HO100304

When the offences from the court don't match with the offences on the PNC

HO100310

Multiple Court Offences with different Results match a PNC Offence

HO100311

Duplicate Court Offence Sequence Number

HO100312

No PNC Offence with this Sequence Number (and it was manually set?)

HO100320

Sequence number identifies a non-matching Offence (and it was manually set?)

HO100328

Unable to determine whether fixed penalty or court case should be resulted

HO100329

Unable to identify correct fixed penalty

HO100332

Offences match more than one CCR

HO100333

Manual match detected but no case matches upon resubmission, suggesting ASN updated or PNC data updated manually before resubmission

Scenarios

Scenario 1

Multiple matches, but same result code, so it doesn't matter which one matches to which

Incoming Records

003 CJ88159 2023-03-11 4027 004 CJ88159 2023-03-11 4027

PNC Records

AAAA/1234 001 CJ88159 2023-03-11
002 CJ88159 2023-03-11

Matches 003 -> 001 004 -> 002

Scenario 2

Multiple matches, but different result code, so we don't know which one matches to which

Incoming Records

003 CJ88159 2023-03-11 4028 004 CJ88159 2023-03-11 4027

PNC Records

AAAA/1234 001 CJ88159 2023-03-11
002 CJ88159 2023-03-11

Exception HO100304 raised