The number of LAs, estimated children and episodes in CIN
| Census year | 2008/2009* | 2009/2010 | 2010/2011 | 2011/2012 | 2012/2013 | 2013/2014 | 2014/2015 | 2015/2016 | 2008–2016 |
| N | N | N | N | N | N | N | N | N | |
| LA† | 148 | 151 | 150 | 150 | 152 | 152 | 152 | 152 | 154 |
| Pupil matching references (PMRs) (cleaned)‡ | 387 413 | 584 456 | 501 136 | 599 425 | 588 602 | 618 498 | 599 898 | 571 429 | 1 761 225 |
| LA child ID (derived)§ | 401 872 | 595 976 | 509 088 | 588 943 | 818 472 | 896 471 | 892 747 | 885 023 | 2 761 155 |
| Episodes¶ | 419 661 | 714 207 | 588 943 | 939 095 | 941 581 | 1 021 432 | 1 018 474 | 1 000 572 | 4 668 623 |
Based on authors’ copy of CIN holding complete episode information between 2008 and 2016. Received from the Department for Education, November 2017.
*Data collection in 2008 began in October rather than April 2008. While retrospective cases were also submitted by many LAs, often going back to or before 1 March 2008, the number of episodes is significantly fewer for this reason.
†In 2009/2010, Bedfordshire Children’s Services (LA ID 820) split into Bedford (LA ID 820) and Central Bedfordshire (LA ID 822), and Cheshire Children’s Services (LA ID 875) split into Cheshire East (LA ID 895) and Cheshire West and Chester (LA ID 896).
‡For children with PMRs in the dataset, PMRs are occasionally missing in some records (particularly during ages when they are older or younger than school age). Different PMRs are occasionally allocated for one child. The displayed figures are for the cleaned PMR variable, after addressing these issues where possible. Further information on the cleaning method is outlined in the online supplementary information.
§LA child IDs do not uniquely identify children, as multiple LAs may use the same ID. Children also acquire new LA child IDs when they move LAs and when they are adopted—meaning we are unable to attribute all records to the same child over time. The displayed figures are for the derived LA child ID variable, combining the original LA child ID and the LA code.
¶The displayed figures include some duplicate cases due to reporting errors, for example, when new cases are opened when children have an existing open case.
CIN, children in need; LA, local authority.