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Growth Vouchers Programme

Last registered on February 01, 2022


Trial Information

General Information

Growth Vouchers Programme
Initial registration date
January 31, 2022

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
February 01, 2022, 6:05 PM EST

First published corresponds to when the trial was first made public on the Registry after being reviewed.


Primary Investigator

London School of Economics

Other Primary Investigator(s)

Additional Trial Information

Start date
End date
Secondary IDs
Prior work
This trial is based on or builds upon one or more prior RCTs.
Small businesses that seek and obtain strategic business advice are more likely to thrive
and grow. Taking business advice can increase productivity, drive sales and improve the
chance of survival in tough economic times.

Yet as many as three in every ten small businesses in the UK may have an unmet need
for business advice. To date, available evidence is associative, and does not establish a
causal link between small businesses taking business advice and their subsequent higher
growth. No one definitely knows whether it is the advice conferred that enables businesses
to be more likely to prosper, or whether advice and growth are two separate and unrelated
consequences of some other unobserved characteristic or behaviour. This is what Growth
Vouchers will test.

The Growth Vouchers programme is a pioneering government research project that aims
to make it easier for small businesses to access expert advice to help them grow and test
which types of business advice are most effective.

The Growth Vouchers programme will run until March 2015 to attract around 20,000 small
businesses that do not normally use advice. Vouchers worth up to £2,000 each will be
given to a majority of the small businesses who take part to help them pay for advice.
This programme will operate as a Randomised Controlled Trial (RCT), which will enable
the government to obtain a robust assessment of the impact of different types of advice on
participating businesses to be obtained. RCTs are widely regarded as the ‘gold standard’
for empirical research and are used extensively in medicine and international
development. This is the first time that an RCT has been run on such scale anywhere in
the world to explore what business advice works best.

The Growth Vouchers programme will produce real and comprehensive evidence, while
providing benefits for the businesses who take part. This evidence will be used to inform
future policy.

This document sets out how the Growth Vouchers programme will operate, how its design
satisfies the principles of running an RCT and the key questions that we aim to answer. It
then explains what data and analysis will be done to arrive at an answer and the technical
constraints on how robust our answers may be.
External Link(s)

Registration Citation

Overman, Henry. 2022. "Growth Vouchers Programme." AEA RCT Registry. February 01.
Sponsors & Partners

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Experimental Details


Eligible firms that completed an online application were offered either an online or personal diagnostic. The diagnostic assessment aimed to establish firm proficiency in each of five areas or ‘themes’ - sales and marketing, raising finance, leadership and management, workforce development and digital technologies. The diagnostic identified one of these themes as an area in which the firm might benefit most from receiving advice. Once a theme of advice was selected, some firms were offered a voucher, capped at £2,000, that could be used to cover up to 50% of cost of the purchased advice. All firms were then referred to an online directory of business advice consultants –developed and run by Enterprise Nation, a business support network for small businesses in the UK.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Number of employees
Secondary Outcomes (explanation)

Experimental Design

Experimental Design
Firms were eligible if they had been trading for at least one year, had less than 50 employees and had not paid for business advice in the previous three years.

All eligible applicants received a personal or online diagnostic which they had to complete to be considered in the random allocation of vouchers. Allocation to the different diagnostics was randomised: 25% of firms were allocated to an online diagnostic and 75% to a face-to-face or telephone diagnostic.

To complete the diagnostic assessment, firms had to select a theme of advice. Then, they were randomly allocated to a control or treatment group. Randomisation occurred within the theme of advice selected, with 75% of firms allocated to treatment and 25% to the control group. The voucher received by the treatment group could be used to cover 50% of the cost of business support and was capped at £2,000. The total cost depended on the business advice selected. The control group only received the diagnostic (online or personal, depending on the initial randomisation).
Experimental Design Details
Randomization Method
Randomization done in office by a computer
Randomization Unit
At the firm level
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
Not clustered
Sample size: planned number of observations
Sample size (or number of clusters) by treatment arms
First randomisation point during business advice assessment: 4,833 online and 14,500 personal
Second randomisation point during allocation of vouchers: 4,833 control and 14,500 voucher
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
In order for the programme to be a success, we set the minimum return on investment at 400% (measured in terms of the increase in business’ turnover). We therefore need to be as confident as possible that our analysis will detect an effect of this magnitude. As is conventional, we aim to have at least an 80% chance of detecting this return (also known as 80% ‘power’). In order to detect a 4:1 return on investment, we need to observe an increase in turnover of £41,150 per business on average. Expressed in terms of our standard deviation, this is an effect size of d=0.108, where d is Cohen’s d, a standard effect size scale for continuous variables
Supporting Documents and Materials


Document Name
Full trial protocol
Document Type
Document Description
Full trial protocol available online
Full trial protocol

MD5: ee78663dff7379e4d066ddc594463d89

SHA1: c360c23458f4e02177e299619078d08c4ade4381

Uploaded At: January 31, 2022


Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number
Analysis Plan

Analysis Plan Documents

Full trial protocol available online

MD5: ee78663dff7379e4d066ddc594463d89

SHA1: c360c23458f4e02177e299619078d08c4ade4381

Uploaded At: January 31, 2022


Post Trial Information

Study Withdrawal

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Is the intervention completed?
Intervention Completion Date
March 30, 2015, 12:00 +00:00
Data Collection Complete
Data Collection Completion Date
March 30, 2017, 12:00 +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
20,283 firms
Final Sample Size (or Number of Clusters) by Treatment Arms
Sales & marketing 2,374 control and 7,203 treated; Raising finance 685 control and 2,009 treated; Leadership & management 735 control and 2,289 treated; Workforce development 234 control and 663; Digital technologies 1,048 control and 3,043 treated.
Data Publication

Data Publication

Is public data available?

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials