The Index of Average Earnings (AEI) is compiled annually, using a “matched pair” approach. The main purpose of the index is to provide a measure of the change in employment earnings.
For a comparison between our AEI statistics and our other earnings statistics, and planned changes to these outputs, please see our earnings statistics explainer. See also the earnings statistics and gender pay gap methodology for more details about those reports.
In all three of these reports, earnings refers to employment earnings. For statistics on household income, including earned and unearned income, see our household income distribution report.
Data sources
The AEI is determined from earnings data collected using from a large representative sample of employers in Jersey using the Average Earnings Survey (AES), and combined with administrative data for all Government of Jersey departments. The survey is compulsory under the provisions of the Statistics and Census (Jersey) Law 2018.
Reference population
The sample frame for the AES is derived from actively trading employers that have a business licence with the Population Office in the Employment Social Security and Housing department, under Article 38 of the Control of Housing and Work (Jersey) Law 2012. This is required for most employers based in Jersey that employ staff locally, including self-employed business owners who do not employ other staff. There are some employers that are exempt from registering for a business licence. The most common exemptions are for:
- businesses with one employee, where that employee is entitled or entitled for work, and is working
fewer than eight hours per week; this commonly applies to self-employed sole traders, but applies to other businesses as well - businesses employing domestic staff who do not work for more than two households; this is mostly for private households employing domestic staff
Sampling
The AES is longitudinal, meaning that employers are kept in the sample for at least two years, as the index is calculated using the change in earnings between two consecutive years.
To ensure a representative sample of Jersey’s employers, a random sampling approach is used to select replacements in the sample. The sample is stratified by size (based on employment on a full‐time equivalent [FTE] basis), meaning businesses are grouped into different size categories and sampled separately to ensure businesses of all sizes are properly represented. The sample is also checked to ensure coverage of all sectors (UK Standard Industrial Classification [SIC] 2007). Size‐dependent sampling probabilities are applied, and employers with more than 50 FTE employees are given a sampling probability of one.
The sample is reviewed annually to incorporate new employers and changes in staffing, in order that the sample remains representative of Jersey’s economy, and to minimise the burden for respondents.
Data collection
Each round of the AES launches on 30 June, and the survey is open for approximately six weeks.
Sampled employers report earnings paid in June if paid monthly, or in the final week of June if paid weekly. This includes the total gross wages and salaries paid to employees before any deductions are made for tax, employees’ social security contributions, employees’ contributions to pension funds, and so on. The reported figures are to include any Jersey weighting allowances, non-contractual gifts and commission. Redundancy pay, directors’ fees and employers’ contributions to Social Security and pension schemes are not included; bonus payments, holiday pay and back pay are also excluded.
Employers are also asked to provide the number of staff covered by the earnings payments reported, including the numbers working full-time and part-time, together with details of hours worked. Part‑time staff are converted into full-time equivalents (FTEs) according to numbers of hours worked. In this way the overall measured change is less susceptible to changes in the proportions of full‑time and part-time employees in the workforce.
Calculations
Mean earnings
From the data collected, the average weekly earnings is calculated for each respondent employer, salaries paid monthly or four-weekly having been converted into weekly figures. The average weekly earnings for each employer is then compared with that of the previous year in order to calculate an annual percentage change. Only employers with a “matched pair” of earnings for the current and previous years are included in the final calculation of the index.
Mean average earnings are aggregated for each sector, in order to calculate a measure of average weekly earnings by sector. These sectoral averages are then weighted together according to the sectoral share of total employment to give the overall average weekly earnings, and hence percentage change between one year and the next.
The AES is designed to measure changes in average earnings by matching records in consecutive years from sampled employers. The figures for the levels of weekly earnings should be considered as estimates with a 95% confidence interval of approximately ±£20. However, the change in average earnings overall (the AEI) is unaffected by the changes in level.
Median earnings
A median average cannot be calculated from the employer-level data collected by the AES, since a median average requires earnings at an individual employee level. Due to this, the Index of Average Earnings report includes median earnings statistics calculated by using data from the Living Costs and Household Income Survey (LCHIS) and uprating in line with the AES. However the LCHIS is only run approximately every five years.
We developed the new administrative data based earnings statistics report to better meet the need for median earnings statistics on a more frequent basis, as well as to provide several other benefits. See the earnings statistics and gender pay gap methodology for more details about the new report, and the earnings statistics explainer for a comparison between the two approaches and our plans for the future of these reports.
Methodological changes
In reports prior to June 2025, comparisons with the UK were made between the Jersey AEI and the Office for National Statistics (ONS) Average Weekly Earnings (AWE) statistics. However, these are less comparable than new statistics published by the ONS and HMRC, so the comparison was moved to our earnings statistics report to provide a fairer comparison between Jersey and the UK.
Data tables
Data tables and supplementary information associated with the Index of Average Earnings can be found on our open data site: Average Earnings Index – Datasets – Open Data