The intervention aims to: (a) present information about the importance and benefits of the four aspects of conscientiousness at work; (b) increase the motivation to change conscientiousness states; (c) provide instructions to activate conscientiousness states; and (d) prompt behavioral practice using reminders to activate the conscientiousness states.<sup>15</sup> The intervention consisted of two components. The first component was a group training session with an average of 24 participants that lasted 2 hours, for eight groups in total. The length of the session and the number of participants were similar to other training sessions that workers received on safety and security. The session was hosted by a professional consultant with experience delivering training of this kind in Senegal.<sup>16</sup> The training was conducted in the local language, Wolof, to ensure that workers fully understood all of the material. During the session, the trainer explained different concepts regarding non-cognitive skills to workers in the treatment group, in particular conscientiousness, with an emphasis on how improvements in such skills can lead to long-term benefits for the worker. The control group did not receive any additional training beyond the standard training provided by the company to all workers, which includes an initial security training at the start of the contract and periodic sessions throughout the duration of the project.

The second component consisted of weekly reminders for eight weeks via short phone calls (less than 1 minute) to activate non-cognitive skills change. Calls were made by a survey company. Reminders were randomized across weeks and all workers received the same set of reminders each week. During each call, workers were given personal skills reminders, such as, “Make sure not to leave your place of work at any time without replacement”, that target conscientiousness. Phone calls were also conducted in Wolof.

A mid-line survey was conducted in January 2020, and an end-line survey was conducted by phone in May 2020. Our sample started with the 386 individuals interviewed at baseline. At mid-line, 344 answered our survey (10.9% attrition), while at end-line we were able to reach 371 respondents (3.1% attrition).<sup>17</sup> Despite the fact that this light touch intervention has a relatively low “dose”, it is expected that the repeated reminders function as triggers that initiate the conscientiousness states in the daily life of the workers and instigate change processes. Skill change can be best elicited through repeating behaviors that differ from typical, trait-like behavior (Allemand and Flückiger, 2017; Roberts et al., 2017; Wrzus and Roberts, 2017). The accumulation of

> an effect.

> 15Full details of the content of the training session are provided in Appendix A.

> 16The consultant has previously led several training programs in Senegal in personal development, conflict management, judicial defense and youth support.

> 17 We lose a further three observations due to missing data on earnings. Appendix Table B.1 compares baseline characteristics of attrition and non-attrition groups. We do not find any major systematic differences between these groups and any statistically significant differences disappear after controlling for multiple hypothesis testing. We also do not find a statistically significant difference in attrition between the treatment and control groups.

7