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Effect on RIDDOR statistics following recent legal and system changes

In the three years from 2011, the following three changes have taken place to the notification of RIDDOR incidents. Some of these changes have had an effect on RIDDOR statistics, so care is needed when comparing one year with another. Below is a summary of the changes and, where known, the effects on the statistics. Covering the most recent change first:

The following describes the above changes in more detail:

Changes to RIDDOR: October 2013

These changes took effect mid-way through the reporting year 2013/14, so any effect of the change will be roughly half that for the full year, although noting there can be seasonal effects, for example bad weather, which could skew the results for the ‘winter’ half of the year since the change. In addition following the changes, there may be subtle effects on reporting behaviour.

One of the main changes in terms of statistics, is the former ‘major’ injury to workers definition changing to ‘specified’. Some of the old major categories were removed, other new ones included. The net result is a reduction of reports of around 10% (full-year equivalent) when comparing the new specified with the old major injuries.  

The over-7-day reporting threshold did NOT change on the above date – it changed the previous year. However, some of the former major injuries that are no longer reportable as specified (as described in the above 10% reduction), still fall within the over-7-day reporting threshold, and reported as such. Typically many of these are dislocations or overnight hospitalisation, previously classified as major, but now reportable as over-7-day injuries. Therefore numbers of over-7-day reports from October 2013 are slightly higher than they otherwise would have been. 

Separate to the above changes, many defined dangerous occurrence categories changed ‘type number’ as well as description.

The reporting of domestic gas incidents resulting in injury also changed. Previously the injury was defined as ‘major’ to qualify; now it requires hospitalisation.

For the above reasons, direct comparison of statistics that span the affected years should be avoided and/or treated with caution.

Further information on the new RIDDOR classifications.

Change to over-7-day injury reporting: April 2012

From April 2012 a legal change to RIDDOR affected the reporting threshold, for those non-fatal injuries to workers that are not ’major’ or ‘specified’. Previously the reporting threshold was over-3-days, now it is over-7-days off work (or unable to do normal duties). However the requirement for employers to retain records of over-3-day injuries still remains.

The net effect is to reduce the previous rate of over-3-day reports by around 29%. No discernable change in major injury reporting was evident following the change. As a consequence of this change it is not possible to make direct comparisons between over-3-day and over-7-day statistics. More detailed analysis of the long-term trend in over-3-day injuries, and an estimate of the effects of the change to over-7-day, has been undertaken. This includes estimated effects on major injuries, by all industry and some main industries.

For illustrative purposes, a description of the relationship between all workplace injuries, and the amount of time off, can be seen through the complementary data source, the Labour Force Survey, showing accidents with: less than 4 days off; 4 to 7 days; and over-7-days. 

Change in reporting system: September 2011

From September 2011 the RIDDOR notification system used by employers changed, with reporting now being predominantly online or automated IT submission. In completing the online form, employers provide information about the incident using simplified drop-down lists. Therefore less detailed information is available compared to the previous reporting arrangements, although most top-level RIDDOR statistics are still comparable. To note, although the actual reporting mechanism changed, RIDDOR itself did not at that time. 
Analysis of data from the new system to date suggests that, whilst the overall numbers are consistent with the previous system, in practice some of the coding and definitions may not be. This problem is frequently observed when administrative systems are changed, and is not unique to RIDDOR. To enable RIDDOR data to be published for the year 2011/12, a new dataset was created for the full-year using data from both old and new systems. This enabled us to publish top-level RIDDOR figures for the 2011/12 by:


A technical description is available, showing the data items (fields) contained in the RIDDOR datasets as used in these statistics:

To ensure data from the new and old reporting systems are comparable, for statistical purposes, HSE statisticians have made the following adjustments to data from the new system. It should be noted that the underlying 'raw' data, as required under RIDDOR and provided by the notifier, remains unchanged.

Industry classification

The reporting system requires notifiers to select from a drop-down list of industry classifications, and aligns to the UK-wide system of SIC ('Standard Industrial Classification 2007'). The information provided by notifiers allows classification at a '4-digit' SIC level. Together with estimates of employment by SIC, this allows injury rates to be calculated, thereby identifying higher and lower risk industries.

Records have been reviewed and re-coded, where the levels of reports for a given industry were significantly higher or lower than those from the previous system. Some other blocks of industry coding were also obviously mistaken. These have been corrected in blocks, where it was practical to do so, but it was not feasible to review reports individually.

This re-coding has been achieved by using additional information from the reports, to decide whether a more relevant industry code is available. For example, there has been an increase in the proportion of 'other industry' selected, and where possible these have been re-coded to a more specific one.

This re-coding enables us to publish industry data at a 2-digit level by main industries like: construction; broad manufacturing types; agriculture; and top-level service-based industries such as retail and types of public administration. A matrix of these 2-digit conversions has been produced.


The reporting system requires notifiers to enter the job title of the injured person, in a 'free-text' format. To enable analysis, this information requires classification according to the UK-wide 'SOC 2010' ('Standard Occupational Classification 2010'). However, many of the job titles provided are too vague to code directly, e.g. production/process/factory worker. Others used job titles that are unknown outside their industry or company. As a consequence, it is not feasible to code a considerable proportion of records with sufficient accuracy and automation, therefore the coding of occupation has ceased and the data no longer available for statistical analysis.

Injury 'severity' and employment status

In some cases, the information provided by the notifier is inconsistent with the definitions set out within RIDDOR. Under RIDDOR only certain types of incident are reportable. This includes:

Additionally, ‘specified’ injuries are clearly defined in RIDDOR, so for example, a fractured arm can only be specified and not an over-7-day injury.

Where invalid values and/or combinations of data exist, these records are automatically re-coded to the appropriate values.

'Material agent' field

That is, the material or substance involved in the accident. This is no longer collected in the new system, hence only available up to 2010/11.

'Kind of accident' field

This data is still collected through a drop-down list, although not at the same level of detail as under the previous system. Data on the more detailed ‘sub-level’ classification is available up to 2010/11.

Date of incident

Each year a small percentage of incidents appear to be reported 'very late'. For example the date of the report might be 6 months or more after the date given for the incident. In practice it is difficult to determine if the report has been made 'late', or an error was made when the incident date was typed. As the majority of 'very late' reports are almost exactly one or two full years 'old' (around 365 or 730 days time lag), it is assumed an error was made regarding the date of incident, and any record more than six months 'old' defaults to the date reported.

Duplicate reports

For a variety of reasons, the same incident is sometimes reported more than once. Where possible such records are excluded from statistical analyses. We use an automated computer algorithm to identify possible duplicate records. Each 'possible' duplicate record is then viewed manually, to avoid records being removed due to 'false matching'.

'Non-reportable' incidents

The new RIDDOR reporting system enables simple and efficient notifications to be made by employers. However, sometimes incidents which are not legally reportable are entered on the system. This was also the case with the previous reporting system.

HSE statisticians identify records which are 'not reportable', and exclude these from analyses. Typically these include road traffic injuries; workplace concerns; natural causes. Further information about what should be reported is available on the RIDDOR website. Further information about what should be reported is available on the RIDDOR website.

Updated 2017-10-26