Experimental Design Details
Our experimental design follows a stratified four-arm randomised controlled trial (three treatment groups + one control).
All firms (including control firms) receive a generic email containing information about training opportunities through the financing channel of the local employment agency dedicated to craft firms in the province. Within the text of the email, an option is mentioned to request further details via a dedicated email address. Treated firms receive the same email, which, at the end, also includes a link to the dashboard mentioned above. The dashboard contains various information on training funded by ADL over the 2022–2024 period: in addition to the number of firms that participated in training initiatives, it reports the average training hours, the average funding provided, and the corresponding totals by sector. When the sector is locked (see below), the values refer to all sectors. Linked to these data are details on the breakdown by type of course (i.e., technical and transversal skills), as well as the list of the most frequently attended course cycles for these two categories.
The treatment group is divided into three arms, which differ depending on the type of training information accessible through the dashboard:
• Treatment 1 - receives information limited to the sector in which the firm operates; we obtain the sector from the administrative database containing the universe of craft firms in the province.
• Treatment 2 - receives the "full” dashboard, allowing navigation across all sectors, but pre-set on the sector in which the firms operate; this implies that when opening the dashboard, firms in this treatment arm see the same page as treatment 1, but are allowed to further browse the dashboard across sectors. They can also see the total for all sectors combined.
• Treatment 3 - receives only information for all sectors combined, without the possibility to browse across sectors or to access information about its own specific sectors. This information is also available for firms in treatment 2 by selecting “All sectors”.
The receipt of the email can be monitored to ensure that generic information about the financing channel is delivered in equal proportion to both treatment and control groups. The email subject line will be identical across groups. Treatment take-up will be measured by the number of clicks on the section of the email linking to the dashboard. A pilot analysis on a small sample of firms predicted a take-up rate of approximately 20%.
Protocol deviations
Amendment note
Implementation deviations: after randomisation, two implementation issues occurred (i) firms assigned to Treatment 2 (T2) did not receive the planned email or dashboard; they did not received anything (no-contact); and (ii) firms assigned to Treatment 1 (T1), received instead T1 plus a second email 1.5 hours later containing the T2 dashboard link (cross-sector navigation enabled). The email body was otherwise identical. We retain the original four-arm intention-to-treat (ITT) analysis by assignment and pre-specify the comparisons that remain valid under these deviations (see Analysis plan).
To sum up, treatment assignment remained randomised, but assignment to the treatment arms deviated from the initial setting. The new configuration is the following:
• Control (C): Generic email only (no dashboard), [no change];
• T3: Dashboard with aggregate/all-sectors only (no sector page, no navigation), [no change];
• T1: Two identical mails but different links to the dashboard (sector-locked plus cross-sector);
• T2: No contact (Super Controls).
From the first summary statistics provided by the Employment Agency, almost three weeks after the emails were sent (01.10.2025), delivery rates among contacted arms were similar (Controls: 4,251/4,579; T1: 2,117/2,291; T3: 2,191/2,369). General take-up (dashboard access) was 10.1% in T1 vs 9.2% in T3, indicating limited behavioural impact of the duplicate email. Among the T1 group (n = 232), it emerges that 40.9% opened only the T1 link, 45.7% only the T2 link, and 13.4% opened both.
Given the results on the take-up, in the reminders scheduled from now on, we will deliver to the T1 group the "cross-sector navigation enabled" dashboard, pre-set on their sector-specific information, but allowing navigation across all sectors.
For these reasons, we keep the four-arm stratified RCT (Control, T1, T2, T3) and we analyse the pre-specified outcomes, considering the following comparisons:
• Any contact vs no contact: (Control + T1 + T3) vs T2 (now Super Controls).
• Dashboard (any) vs generic email: (T1 + T3) vs Control (restricted to contacted arms).
• cross-sector (pre-set on their sector-specific information) vs aggregate: T1 vs T3.
To maintain a consistent definition of T1 exposure, subsequent reminders to T1 will include the cross-sector dashboard (pre-set on the firm’s own sector, with navigation enabled). C and T3 reminders remain as originally defined; T2 remains a no-contact group for the whole intervention period.