Methodology

Children's social work workforce: attrition, caseload, and agency workforce

Published

Background and coverage

Background

The data used in this release is the children’s social worker workforce census, collected by the Department for Education. Information on the main release can be found here, and details on the main release’s methodology can be found here

Users should read all footnotes and caveats included in this ad hoc publication to understand the practical applications and limitations of the data. In particular, comparisons with previous years should be done with caution. Please refer to the ‘Data quality’ section for more information on data quality issues.

This is the first release in this series. It covers two years of data, starting from 1 October 2019. Both years of data may be affected by the coronavirus (COVID-19) pandemic. Due to the coronavirus pandemic, and only two years of data in the release, longer term trends should not be drawn between the two years of data in this release.

Coverage

The children’s social work workforce census covers all local authorities in England and all children's social workers employed by those local authorities.

Kingston upon Thames and Richmond upon Thames submit a joint return each year, and the numbers are reported against Kingston upon Thames. This arrangement has no impact on regional and national totals.

Northamptonshire local authority was replaced with two new unitary authorities, North Northamptonshire and West Northamptonshire, in April 2021. Data for both unitary authorities is reported against North Northamptonshire in this publication. 

Data collection

Data used in the current ad hoc statistics release use data from the Children’s social work workforce collection. 

Data were collected at an individual social worker level and figures in this statistics publication are shown at full-time equivalent basis only.

Definitions

Children's social workers

Social workers who were in a local authority-employed children’s social care role on 30 September of the reporting year. Social workers can be employed by a local authority directly, or employed by an agency. Each of these workforces are recorded and reported separately.

Full-time Equivalent (FTE)

Full-time equivalent (FTE) figures are derived by aggregating the total number of hours that staff are contracted to work and dividing by the standard hours for their grade. 

Leavers

Social workers who were recorded as leaving a children’s social care role between 1 October of the reporting year and 30 September of the reporting year.

Attrition from LA employed children’s social work

Social workers who were recorded as a leaver (as above), and were not observed in an LA-employed children’s social care role as of 30 September of the reporting year.

Attrition into agency social work

Social workers who were recorded as attrition from LA employment (as above), but were observed as an agency children’s social worker on 30 September of the reporting year.

Full attrition from children’s services in local authorities

Social workers who were recorded as attrition from LA-Employed children’s social care, and were not re-observed in any other children’s social care role as of 30 September of the reporting yea

Movers

Social workers who were recorded as a leaver (as above), but then were observed as an LA-employed children’s social worker on 30 September of the reporting year.

Cases

A case is defined as any person allocated to a named social worker, where the work involves children's social work. This may include: 

  • an individual child allocated to a social worker (for example, a family of three siblings where each child is allocated to a social worker counts as three individual cases) including those on a child protection plan, children in need, fostering and adoption cases and care leavers
  • a carer or carers allocated to a social worker for the purposes of fostering or adoption.

Cases may be held by social workers regardless of their role in the organisation and not just those specifically in a ‘case holder’ role.

For additional information, please see the official statistics methodology.

Age

Age is derived from the date of birth provided in the census and is age at 30 September of the reporting year. 

The same age group breakdowns as in the official statistics children’s social work workforce publication are used.

Time in local authority

Time in local authority (LA) is derived from ‘role start date’, which is collected in the census and is a measure of the length of time in a children’s social worker role at the social worker's current local authority.

Calculations

Number of local authority social workers in post at 30 September

The number of local authority (LA) children’s social workers at 30 September of the reporting year. It does not include agency workers, who are covered separately. If a social worker left their post on 30 September, they are counted as both in post and as a leaver during the reporting year.

Number of social worker leavers during year ending 30 September

The number of children’s social workers with a leaving date during the year ending 30 September. The calculation for FTE leaver figures are based on FTE at 30 September of the previous reporting year:

  • for leavers during the year ending 30 September 2021 this is their FTE at 30 September 2020.
  • for leavers during the year ending 30 September 2020, this is their FTE at 30 September 2019. 

Turnover rate 

The turnover rate is calculated as the number of FTE children’s social workers leaving a children’s social work role in their current local authority in the year, divided by the number of FTE social workers in post at 30 September.

Attrition rate

The attrition rate is calculated as the number of FTE children’s social workers leaving a children’s social work role, and then not observed in a local authority children’s social work role on 30 September of the reporting year, divided by the number of FTE social workers in post at 30 September. 

Attrition into agency rate

The attrition into agency rate is calculated as the number of FTE children’s social workers leaving a children’s social work role, and then observed in an agency children’s social work role on 30 September of the reporting year, divided by the number of FTE social workers in post at 30 September. 

Full attrition rate

The full attrition rate is calculated as the number of FTE children’s social workers leaving a children’s social work role, and then not observed in any children’s social work role on 30 September of the reporting year, divided by the number of FTE social workers in post at 30 September. 

Time in local authority

For social workers in post at 30 September, time in LA is calculated as the time in years between the dates the social worker started employment in children’s social work at their local authority, and 30 September of the reporting year.

For social workers who left their post during the year, time in LA is calculated as the time in between the dates the social worker started and ended employment in children’s social work at their local authority.

Agency worker rate (FTE)

The FTE agency worker rate is calculated as the number of FTE agency staff working as social workers at 30 September, divided by the sum of the number of FTE agency staff working as social workers at 30 September and the number of FTE social workers at 30 September. 

Average caseload per FTE

The average caseload per FTE children’s social worker is calculated by taking the total number of cases held by each children's social worker (including agency workers), divided by the number of FTE children’s social workers (including agency workers) who have a number of cases greater than zero. For visualisation purposes, number of cases per FTE were rounded up to the nearest whole case, so 15.2 case and 15.7 cases would both be rounded up 16 cases.

Additional attrition estimates

An additional estimate of attrition based on leavers from the first 6 months of the collection period is calculated. The FTE of leavers and attrition are doubled, to produce an estimate for a whole year.

A further estimate of attrition is also produced, based on leavers from only the first month in the collection period, October 2020. The FTE of leavers for October 2020 is divided by 31 to calculate a daily FTE estimate. This is then multiplied by 365.25 to calculate a yearly estimate, accounting for a leap year.

Time between roles

Time between roles is calculated as the number of days between social workers who moved from a children’s social worker role to another children’s social worker role in the year ending 30 September 2021.

Data processing and cleaning

Data cleaning

For general background information on the data cleaning process for the children’s social work workforce, please see the methodology of the official statistics children’s social work workforce publication.

For the attrition analysis included in this ad hoc publication, additional data cleaning was performed to be able to link social worker records within each year. This included changing the prefix to registration number to allow joining, affecting less than 1% of registration numbers.

Where two or more records in the same group had the same registration number, these were combined into a single record with FTE and cases held summed together. Note: This method reduced the overall FTE of the local authority (LA) employed workforce by 1 FTE. Agency-employed workforce data, and the data of leavers from LA-employed social work were unaffected.

 

Data processing

Attrition analysis

Social worker census data were split into the LA workforce, leavers, and the agency workforce. Leavers were then matched against the LA workforce, using registration number. Social workers appearing in both datasets were defined as the movers group, with social workers only appearing in the leavers dataset being defined as the attrition group. 

This process was repeated, matching the attrition group and the agency workforce. Social workers who appeared in both groups were defined as the attrition into agency group, and social workers who only appeared in the attrition group being defined as the full attrition from children’s services in local authorities group. 

These groups were then split into age groups, and into groups based on their time in LA to provide insight into the different groups of attrition (see definitions for details of age and time in LA). Total FTE and rates for all groups were calculated.

Additional analysis based on the number of days between roles for the social workers identified as movers between local authority posts was also conducted (see definitions and calculations sections for details).

Agency Workforce analysis

Agency Rate

Individual level data from agency-employed social workers on 30 September, and the LA-employed children’s social work workforce on 30 September were used calculate the agency rate of each local authority in England (see calculations section for details). 

Organisation roles

Individual level data from agency-employed and LA-employed children’s social workers were used to calculate the proportion of each workforce which are employed at each role type (see the children’s social work workforce for details on roles types).

Caseload Analysis

Individual level data from the local authority (LA)-employed and agency-employed children’s social work workforces were used to calculate the number of cases held per FTE (see calculations section for details). 

Data quality

For general data quality of the children’s social work workforce data, please see the “data quality” section of the children’s social work workforce methodology.

Some known data quality issues specific to the analysis presented in the ad hoc publication are listed below:

Duplicate records

For information on the removal of duplicate records for the official statistics release, please see the methodology of the children’s social work workforce.

Where two or more records in the same group had the same registration number, these were combined into a single record with FTE and cases held summed together. Note: This method reduced the overall FTE of the local authority (LA) employed workforce by 1 FTE. Agency-employed workforce data, and the data of leavers from LA-employed social work were unaffected.

Attrition and attrition rates

To determine attrition FTE and attrition rates, leavers are joined with the LA workforce and the agency workforce at two separate stages. Issues around social workers not starting their role by 30 September, or issues with registration numbers in data collection, may cause a small over-estimation of attrition. We cannot yet quantify the scale of this.

Time between roles

Some social workers were identified as starting their new role before leaving their original role. These differences ranged from one day, to multiple years. All records which showed a new role starting before the original role had ended were removed from analysis (246 FTE children's social workers removed). Also, social workers who left their role on 30 September were excluded for analysis, as the days between roles would be a maximum of zero for each of these records (50 FTE children's social workers removed).

Cases held and caseload per FTE

Some social workers were reported to be holding over 50 cases per FTE. It is not known whether these are data entry or data recording issues, or reflective of true caseloads. For the overall number of cases held, and breakdown of cases held at each organisation role, these records are retained in order to remain consistent with the official statistics. 

For the chart on cases held per FTE, these records are removed from analysis as outliers (the average caseload for year ending 2021 was 16.3 cases). Footnotes are included on caseload analysis for transparency.

Similarly, there were 309 social worker records which were recorded as holding cases, but stated their role was 0 FTE. A figure for the number of cases per FTE could not be calculated for these social workers, so these records were removed from the caseload chart.

Qualified without cases

Some local authorities may have difficulty assigning social workers into the role types which are recorded in the data collection. Some social workers may be employed in a role which holds cases, but their role does not meet the description of any other role type (such as chair of child Protection conference, or family support worker; see census guidance of the children’s social work workforce for more details). Where this occurs, local authorities may report the social worker as being in a “qualified without cases” role type, despite holding cases. For this reason, some social workers in the qualified without cases role type do hold cases, though this is a small proportion for both agency and local authority social workers.

Uses of the data

The main internal users of these statistics are officials within the department, who use the information to provide advice to ministers on current and future policies.

The main external users of these statistics are the Independent Review of children’s social care in England. Other external uses of these statistics may be local authorities, Ofsted and the Children's Commissioners office for England as extensions of the official statistics publication of the children’s social work workforce.

Confidentiality and rounding

The Code of Practice for Statistics requires we take reasonable steps to ensure that our published or disseminated statistics protect confidentiality. Suppression of small numbers has therefore been applied to the data, where it is applicable to do so. 

The following rounding conventions have been used: 

In the main text, figures for FTEs have been rounded to the nearest 100 or whole number. Rates and percentages have been rounded to the nearest whole number or to one decimal place.

In the underlying data, figures for FTEs, rates and percentages have been rounded to one decimal place. 

The following suppression conventions have been used: 

  • 0 Where any number is shown as zero (0), the original figure submitted was zero.
  • z  Not applicable
  • x  Not available

These conventions are consistent with the department’s Statistical policy statement on confidentiality.

Related statistics

Children’s social work workforce: statistics on the children’s social work workforce in local authorities.

Children in need and child protection: statistics on children referred to and assessed by children's social services.

Children looked after in England including adoptions: statistics on children under local authority care.

Vulnerable children and young people survey: summary of local authority survey data in England to help understand the impact of the coronavirus (COVID-19) pandemic on children’s social care.