Feature Article: Usability in ACGT
Combined usability methods and procedures in ACGT
The use of computers, software applications and IT in daily medical life and in research is rapidly increasing. The main task to ensure the usability of the systems developed is to accomplish what the users need. Generally, software is developed without much evaluation during the development process. To avoid this well known risk, it is of utmost importance to involve the end-user from the design phase of new software, during the development process and to secure an iterative evaluation of the software by end-users.
Without taking the end-user into account the software will fail usability at the product stage and end-users would not use the software and the platform what a serious loss of time, money and resources for the project.
To assure the usability, criteria has to be defined, that
- can be used as a guideline for the end-user and helps him to evaluate the software (most of the end-users are not used to evaluate software)
- provides an efficient feedback for the developer to optimize his software
Simplified, the expectations for software systems are two fold:
- The software must do the right things: software systems must do what they are supposed to do (end-user perspective)
- The software must do the things right: software systems must perform the tasks correctly (developer perspective)
To assure that the software used in ACGT will meet the high demands of the end-users needs, the usability must be clearly defined and guarantee that:
- The software developed by ACGT is evaluated by the end-users throughout the development period
- The software implemented in the ACGT platform fulfils the requirements for usability of the ACGT main target groups
The individual specifications and functions of new software must be defined from case to case.
The end-user usability criteria of software are part of the top-down perspective and various categories of end-users are defined and criteria in terms of its suitability to achieve its intended goals are given.
To produce usable software for the target users and to reduce unnecessary implementation costs during the development, it was important to start very early with the usability process. This causes to consider the needs of the end-users with the whole context of use.
A usability engineer will accompany the whole development process and conduct the usability tests with the first developed prototypes. During the life-time of the project he has the functionality of an independent agent between the end-users and the software developers. For the success of ACGT it is on high importance that the software is self-explanatory and easy to use, because the main user groups have none or basic knowledge of computer systems or applications. The user interfaces are of fundamental impact as a gateway between project and end-users.
A couple of tools are developed in ACGT for different target groups. To these target groups belong clinicians, biostatisticians, software developers, consultants, patients and the general public. The needs of these end-user groups as well as the use of the platform itself are separated.
Usability and End-user driven design in ACGT
Many standards are related or affect the usability of computer software and applications. These standards have to be taken in account during the development process. For the evaluation of usability regarding developed software and tools the ISO 9241-11guidance of usability is the most relevant standard as it describes an objective, structured process to identify the users' requirements for the software and the mechanism to modify software applications and procedures with regard to the functionality and usability of the software. To respect the complexity of the ACGT project, the standard IEEE 830 is used to comprise the software developer needs.
The applied usability method in ACGT is based on the DATech Test Handbook. DATech is the German accreditation instance of laboratories in a variety of fields of technology. The Test Handbook is only written in German and can be accessed at www.datech.de. It offers a guideline for usability professionals to test the usability of interactive systems, in particular corresponding to the international standard of usability (DIN ISO 9241 part 11 to 17 and 110) and to the user-centred design process (DIN ISO 13407).
To define the requirements for usability for the software and tools the following three major target groups have been taken into account which will use the software in their daily work:
- the clinicians
- the administrator (trial chair) and
- the biostatisticians.
The first four interviews were taken with one clinician, the administrator (clinician) and two biostatisticians from different institutions. These interviews were documented in an objective report which is sent to the end-user for evaluation and to the software developer for achieving a common understanding of the whole task. The written context scenarios cover important and realistic aspects of clinical trial data mining and respectively analysis methods the statisticians are working with. They describe the real life situation of the employee/end-users taking into account.
As the clinician needs a functional and easy to use interface, the biostatistician has to get information on the interoperability and internals of the software and the tools for efficient and effective analysis of the clinical data. The administrator has all rights of the software and should use the clinical tool in an easy and efficient way, too. The user's aim is to conduct his task supporting by the system in an efficient and satisfied way, e.g. to reach his/her goals with minimal effort.
When the first prototypes are developed the next stage of usability activities will take place, namely the usability tests with potential users. These users are clinicians and biostatisticians. In a later phase patients are also involved in this process. Use scenarios result from the usability tests. They are written to identify the problems the user will have when conducting his task.
In general a use scenario describes the user interaction with the aim to identify problems related to the interaction, to denote norm conformity and to discover critical incidences and weaknesses of the system. The use scenario is based on the evaluation of the context scenario in which the minimal functions and requirements of the system were derived from the users implied needs. During the use scenario the usability engineer is involved as an observer. The usability engineer records only the direct interaction of the user with the system, excluding the general behaviour except the loud thinking denoted by "thinking aloud".
The use scenario template is divided into four columns. The first column describes the task to be executed by the user with the system. This task can be subdivided into several mini tasks.
Column number two describes the process, during which the user interacts with the system and his loud thinking of his actions. Additionally, column two tests the behaviour of users in an unsuspected reaction of the system, like a system error. The third column reports the reaction of the system in detail (errors, failure, messages, etc.) and the fourth column analyses the single task process respecting on the norm of conformity or violation norm.
In contrast to use cases the use scenario gives more detailed information about the problems that the end-user will have during performing his task. A use scenario identifies the weaknesses and violation of the system. A use case shows only the action of the end-user and reaction of the system. For evaluation purposes by end-users it is more fruitful to write use scenarios with detailed documentation of the human-system interaction.
The usability engineering process describes a pragmatic approach for interface design, which emphasizes on empirical methods and operational definitions of user requirements for tools concerning software ergonomics. To define these requirements the usability engineer defines the users' needs in relation to his working place and the software concepts or developed prototypes. In ACGT this process is performed during the prototyping period to assure that the users' needs are satisfied.
Marie-Luise Christ-Neumann