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Gymnaste: A Nurse Planing Package in CHIP GYMNASTE is a software package resulting from a successful collaboration of COSYTEC with the University of Joseph Fourier (Grenoble) and PRAXIM. Designed and built with CHIP V5, the Second-Generation Constraint Programming Technology from COSYTEC, it is already in use at the BLIGNY Hospital, situated to the south of Paris.
GYMNASTE is a complete software package capable of automatic construction of time-tables for nurses, with reporting facilities to interface to pay and human-resource departments

The public health service in France is made up of some 40000 health care units regrouped in hospitals, polyclinics or laboratories. Each unit contains from 10 to 60 persons of various skill levels and typically operates around the clock, every day of the year. Staff costs take up to 70 % of the total operational costs of a hospital. Absenteeism is typically about 12 % today in France.

A typical health care unit is under the responsibility of a head nurse, who builds the duty roster for nurses, health assistants, cleaners and servers. This tedius task of building monthly forecasts in line with rules and regulations, handling last-minute changes such as sick leave or individual wishes and reporting back to the hospital administration, takes up to 40 % of her time. GYMNASTE is designed to automate this task.

Gymnaste: A Nurse Planing Package in CHIP

Nurse Rostering

Nurse rostering consists of assigning shifts and rests to nurses for each day of the scheduling horizon, to satisfy given needs per skill level, per shift and per day. Of course, legal and union rules must be taken into consideration, as well as individual wishes.

This problem has been discussed in literature for many decades now. Many methods have been studied, including linear programming, dynamic programming, etc. However, no single application has been used in more than a few hospitals, and no packaged products have been made available.

The cause is mainly due to the contradictory nature of the problem: there is probably no solution satisfying all applicable constraints and preferences. However surveys reveal that individual wishes are often considered more important than legal constraints !

GYMNASTE: End to Headaches !

GYMNASTE is a package based on CHIP global constraints to automate timetable construction, formulated as a discrete combinatorial problem.

GYMNASTE allows head nurses to parameterise the constraints representing work rules and/or personal preferences. The flexibility of the tool allows the construction of monthly forecasts and the modification of partial rosters in reacting to daily incidents. The head nurse can negotiate with the personnel interactively, in building a roster that is globally satisfactory. This aspect is often neglectedin previous approaches to build timetables.

Gymnaste: A Nurse Planing Package in CHIP

GYMNASTE Constraints

The GYMNASTE solver assigns working shifts (such as morning, evening and night defined by the user) to each person for each day of the planning horizon.

GYMNASTE makes available several families of generic constraints that can be used to express different work regulations and laws. End-users parameterise instances according to their specific context. Individual preferences may be expressed either positively or negatively. The personnel may express preferences for given shifts on given days.

Some constraint families are: Transition constraints between assignments exclude for instance, a morning shift following a night shift. The team composition constraint allows tutor and trainees to work together a given number of times per month. Distribution constraints restrict the number of shifts assigned consecutively to a worker.

The software distinguishes between full time and part time staff, and manages meal breaks. It also maintains user-defined counters to ensure equal treatment (e.g. number of shifts worked so far).

GYMNASTE: an “off the shelf” package

Available as a stand-alone application or part of a network server system, GYMNASTE can be integrated within personnel management systems forecasting the timetable for the next month. It takes as input daily needs for various categories of personnel. As output, individual assignments for each person are provided to meet requirements while respecting all given constraints over a horizon of several weeks.

With input from clock-in machines for the current month or entered via the user interface, it can be used to react to absences by making on-the-spot changes or re-planning. Groups of assignments may be locked and others be freed or hand-instantiated for subsequent re-planning by GYMNASTE.

Finally, statistics for the past month may be consolidated and exported to the pay and man-power offices.

The same application can be used by different categories of personnel: the software understands and gives different access rights to different user profiles, as parameterised by the administrator.

The graphical interface of GYMNASTE is interactive and user-friendly, especially designed for casual computer users.

Three-fold Benefits of GYMNASTE

GYMNASTE offers directly perceived benefits to the hospital administration, the head nurse as well as the personnel.

  • The benefit for the hospital administration is the computerisation of rosters, allowing timely and cost-effective feedback from all health care units spread over a wide area and a better management of available resources to handle unforeseen problems. Without re-entering data, the pay office will get detailed work times and the personnel manager can keep accurate work records.
  • Even team workers will see benefit in the deployment of the software. Instead of being considered too complicated or time-consuming, individual preferences will effectively be able to taken into consideration by the head nurse. Equal treatment can be enforced since GYMNASTE keeps track of key assignment figures, as well as a set of counters parameterised by the end-user.
  • The professional activity of nurses have a very heavy influence on their family life. By making rostering a transparent process (through annual counters) and allowing expression of personal preferences, satisfied workers would lead to lower absenteeism and better productivity. Hence the hospital would have lower costs hiring extras while improving the quality of the service.


GYMNASTE has been installed and is in regular use at the Bligny Medical and Surgical Centre since fall 1997. Situated to the south of Paris, it is installed in 11 offices, using clients connected to Windows NT servers.

Authors: G. Weil (UJF), K. Heus (PRAXIM), P. Chan (COSYTEC)

a result of a successful partnership among

PRAXIM Université Joseph Fourier

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