Skills-based volunteering at a rehab center

Skills-based volunteering at a rehab center
Skills-based volunteering at a rehab center
Volunteering work is always needed and very much appreciated. And basically anyone can do it, no matter what limitations, possibilities or knowledge they possess.
And it is exactly the latter, namely a somewhat differentiated knowledge, that Ricardo Saldanha put to use in helping a drug and alcohol rehabilitation center, by giving them the possibility of having the best workforce management in times of COVID-19, and beyond.
Skills-based volunteering at a rehab center


Ricardo Saldanha, Head of Innovation @SISCOG  |  5 min read 



As a volunteer in Vale de Acór, a drug and alcohol rehabilitation center near my hometown, I had an unusual request from management a short time after the first COVID-19 wave arrived in Portugal.

Because they knew I had experience in developing software for workforce management at SISCOG, they asked me if I could help them in planning the work of the rehab therapists in a way that coped with the increased need of assistance and monitoring on behalf of the resident patients (hereafter residents) due to the COVID-19 restrictions.



Vale de Acór is an inpatient rehabilitation center located in Almada, Portugal, that helps people getting free from addiction to drugs and alcohol. More information about this non-profit organization can be found here:





When COVID-19 arrived in Portugal, residents of Vale de Acór became under stress due to increased isolation imposed by the COVID-19 restrictions.

In order to overcome these challenges management decided, among other things, to improve monitoring and assistance by extending the period of the day during which residents have access to therapists. In order to do that, instead of having all therapists working from Monday to Friday from 9am to 5pm, they decided that therapists should work in three shifts covering the period from 8am to 7pm. Since some shifts were more attractive than others, for the sake of fairness, they wanted the therapists to alternate shifts.

Another concern from management was that therapists should meet with other therapists, but not with the same colleagues all the time. In this way, they could learn from each other and exchange information.

Since management felt they had lack of skills to develop a work schedule that met all these requirements, they called me for help. After some brief discussions we came up with the following list of requirements:

  1. The work schedule should be for 12 therapists
  2. Therapists work from Monday to Friday
  3. Therapists should work in 3 shifts (A, B and C)
  4. For each working day the number of therapists in each shift should be the same
  5. Each pair of therapists should be on the same shift at least once in a while
  6. Each therapist should perform all shifts the same number of times




After analyzing the requirements I came up with the following solution design:

  1. The work schedule should be in the form of a roster where lines represent workers (or schedules) and columns represent days of the week. A roster defines, in a compact form, a working pattern that repeats itself as many times as needed. In this context compactness is an important feature as it helps reduce complexity.
  2. In order to meet requirement 1 the rosters should have 12 lines.
  3. In order to meet requirement 2 (3 and 6) the size of the roster line, measured in days, should be a multiple of 5 (3).

Table 1 shows the proposed roster.
As shown, each of the 12 lines (requirement 1) defines a 3-week period with 15 working days (requirements 3 and 6). Furthermore, we can see that each line covers all shifts 5 times each (requirement 6) and each day covers all shifts 4 times each (requirement 4).
We can see that requirement 5 is satisfied by looking at Table 2. The number shown in position (i, j) represents the number of times therapists and are working in the same shift. As shown, all pairs of therapists meet at least once every three weeks.


Table 1. Roster for 12 therapists working in 3 shifts (A, B and C) along a 3-week period (main table).



Table 2. Matrix showing the number of times each pair of therapists work in the same shift (auxiliary table).


In order to obtain the solution presented in Table 1 an excel sheet was built with the same structure as shown in Tables 1 and 2.
The values shown in grey in Table 1 (hereafter main table) were computed by formulas as well as the values inside Table 2 (hereafter auxiliary table). We started by filling the main table column by column, from left to right, distributing 4 shifts of each type in a way that increments by one the largest amount of values equal to the minimum value found in the auxiliary table (which at the beginning of the process is 0). By doing so, we ended up with an initial solution that complied with all requirements except for requirement 6. In order to achieve compliance with that requirement we started swapping shifts belonging to the same column of the main table. Swappings are done between lines with unbalanced distribution of shifts (which can be easily checked by looking at columns A, B and C of the main table). If the swapping produced a more balanced distribution of shifts in both lines and did not result in a zero number appearing on the auxiliary table, than a next iteration is performed, otherwise the swapping is undone and a next iteration is performed. The process ends when all lines are perfectly balanced with 5 shifts of each type in each line.

Instead of assigning each roster line shown in Table 1 to a single therapist, and letting him repeat that line of work forever, we decided to let therapists change roster lines every 3-week period according to what is shown in Table 3. By doing so, we introduced more variety in the lines of work of individual therapists and achieved more uniformity in the number of times therapists meet with each other.


Table 3. Final work schedule for 12 therapists along a 18-week period. 




The work schedule was delivered in a short time to Vale de Acór. After that, Vale de Acór had some internal discussions, introduced some adjustments in the schedule and put it in operation.

The feedback I got from management was very positive. The work schedule, which is still being used in practice, helped operationalize a solution that allowed therapists do their job while providing the residents assistance over a larger period of time. Moreover, Vale de Acór is considering keeping with this work schedule even after the pandemic is over, because it provides a greater benefit for the residents.

This feedback was the best reward I could ever get. I never thought my professional skills, developed at SISCOG, could one day be used for social purposes. I'm quite happy with that.



Gathering of residents in the rehab center (Photo credits: Vale de Acór).