Keywords

1 Introduction

In recent years the use of the mobile device (phones, portable audio players, personal digital assistants, GPS (Global Positioning System) navigators, tablets, digital cameras, etc.) has increased considerably, which is why it is important to have methodologies, elements, and tools that allow to carry out specific usability studies for applications developed for this type of devices [1], specifically for applications that were developed to run on mobile phones. The term mobile refers to being able to access data, applications, and devices from anywhere. [2], for this reason, to software development of this kind, certain restrictions that the hardware has and the context where it will be used must be taken into account, however, the methods, metrics, and guidelines currently used to define usability have been created for desktop applications or web, which may not be directly suitable or appropriate for mobile environments [3], besides, there is an absence of clarity on how to apply this usability in more specific contexts [4]. One of the main challenges is to identify the additional variables related to the use environment and the context, which can impact the usability of a mobile application so that when designing, these variables can be included [3].

This is why this paper focuses on defining a set of usability guidelines for software development in the specific context of the design of interactive mobile applications for learning mathematics in children aged 6–7 years, which were derived from existing usability guidelines, an analysis of the context and its needs. Taking into account that the field of education is incorporating new supports, tools, or technologies that favor student learning processes [4, 1]. However, each application has its own particularities in relation to human-machine interaction that affects the handling and design of its interfaces, as well as the function and uses they may have in a given environment. [4]. For this reason, this paper intends to show an initial version of the set of guidelines to which their completeness, suitability, ease of use and ease of learning were validated, through the judgment of experts, using the multi-cycle action research methodology with a branch of three cycles. According to the results, it can be said that the guidelines are completeness, easy to learn, moderately usable and moderately suitable; determining that there is a need to continue improving its description so that they can adequately satisfy the objective for which they were created, however, we believe that the resulting guidelines represent a good contribution to the usability engineering knowledge field.

This paper is structured as follows, section two: related works, section three: the methodology that was carried out, section four: validation and finally, section five: the conclusions and future work.

2 Related Work

The objective of research of Videla et al. [5], was to determine the elements, components, and factors that are key when designing interactive interfaces for augmented reality environments, focusing in particular on the development of virtual environments for educational applications. For this study two applications of augmented reality of educational content were carried out and tested and whose purpose was to be a complement to the textbook, which were designed for non-tactile interfaces and in which the use of a Webcam and a computer.

On the other hand, Collazos et al. [6], define a guide to correctly include usability in interactive television, and shows evaluation methods to verify its good design. This work described and structured a set of guidelines that can be followed by user interface designers to achieve services clearly adapted to the interactive environment of television. Similarly, there was a project in the UTM (University Technical of Manabí) that focused on the development of educational applications for mobile devices called Edumóvil. It is a project that was born in the UTM and had as its objective: to improve the teaching-learning process of basic level children through the incorporation of mobile technology in the classroom [7], It was focused on developing applications for PDAs (Personal Digital Assistant) and cell phones that covers primary subjects, such as Spanish, Mathematics, History and Natural Sciences, this development an application consisting of a collaborative game for the subject of Natural Sciences and a story viewer aimed at the subject of Spanish [7].

From the viewpoint of education, there are projects such as the one defined by Ocsa et al. [8], which aimed to systematize the design and development of m-learning applications through two types of applications, the first one inter-active in comic format about the foundation of the Inca Empire and the second in book format Interactive about the main tourist sites of Peru, which was intended to reduce the complex development of these applications through encapsulations of native code for mobile operating systems, allowing to establish design and development guidelines for high quality mobile educational applications, in addition, to Consider elements of human-computer interaction, user-centered design as the basis for the development of case studies in order to reflect the scope of applications from a pedagogical and technological viewpoint. Similarly, Tello and Yautibug [9], took into account the current influence of Virtual Learning Environments (VLE), where its development and design is of great relevance for its context of use, therefore, they identified and implemented criteria of good usability practices to detect design errors in the VLE of the National University of Chimborazo and thus increase its level of usability.

The previous works show different methods to evaluate usability in various contexts and applications, but none are related to a specific context of usability guidelines for the design of interactive mobile applications for learning mathematics in children from 6 to 7 years old, that is why in this work, a set of these guidelines is proposed to further guide this process.

3 Methodology

This research was developed following the multi-cycle action-research methodology with bifurcation [10] for which cycles were followed: conceptual cycle, methodological cycle, and evaluation cycle.

3.1 Conceptual Cycle

This cycle consisted of carrying out an analysis of the literature, to identify the existing usability guidelines, as well as to gather important information about concepts, design guidelines, guidelines and elements necessary to include usability in this context. This process showed that most of the guidelines were focused on a web context and desktop applications regardless of context, and lacked a clear explanation for their application. For the development of this cycle, the following activities were carried out as shown in Table 1 Conceptual cycle.

Table 1. Conceptual cycle
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3.2 Methodology Cycle

This cycle consisted of analyzing the information obtained previously, selecting the useful elements and defining the necessary ones that allowed to create a first version of the guidelines for the context of this paper. Table 2 shows the activities carried out in this cycle.

Table 2. Methodology cycle
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For this cycle, a survey was conducted with 9 teachers from the municipality of Puerto Tejada and 1 teacher from the city of Popayan. The survey consisted of 7 open questions, in this way, more than questions, a dialogue was held with each teacher. These questions were developed in order to obtain information on the topics in which the most difficulties are presented among students, the topics that seek to be supported by the application, in the same way, to socialize the idea and see the opinions and ideas of teachers that will help to solve the missing needs that had not been identified.

After analyzing the data obtained, it was determined that the strongest needs in mathematics on the part of the children were in the sum, which is why it was defined as the topic to be treated of the applications to be designed, in addition to defining that these applications must be used by the child for an approximate time between 10 to 15 min. From the survey, some missing guidelines were also defined in order to meet the unidentified or missing needs related to the context.

As a result of this activity, the definition of a format necessary to describe each guideline is obtained, which contains an identifier, a name, a category, a brief description, the steps to be followed, and an illustrated example of applying the guideline. In addition, the first version of the list of guidelines is obtained with a total of 56.

To improve the first version of the guidelines, the standard 9241-11 of usability is taken into account which contains 3 fundamental characteristics that are: effectiveness, efficiency, and satisfaction [11]. These characteristics were redefined for the context of this work, and each guideline was classified into each characteristic. With this classification, those guidelines that do not comply with any of the characteristics of the standard are discarded and, as a result, we obtain a second version of the list of guidelines, generating a total of 39 (See the list of guideline names on Table 3, see an example of the guideline definition on Table 4).

Table 3. List of guideline names
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Table 4. Guideline example
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3.3 Evaluation Cycle

This cycle allows evaluating the completeness, suitability, ease of use and ease of learning of the second version of the usability guidelines. Table 5 the activities carried out in this cycle are shown.

Table 5. Evaluation cycle
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For the development of this cycle, a validation of the guidelines was carried out through a survey aimed at experts in usability, validating its completeness, suitability, ease of use, and ease of learning, for the design of interactive mobile applications for learning mathematics in children aged 6–7 years.

4 Validation

The objective of this validation was to evaluate with experts in usability issues the completeness, suitability, ease of use, and ease of learning of the guidelines developed for the design of interactive mobile applications for learning mathematics in children 6–7 years. This validation was carried out with 6 experts in the area of usability, of which 66.7% have more than 5 years of experience in the area of usability and 33.3% have between 1–5 years of experience.

Each of the experts was given the compendium of the guidelines, in addition to a survey link for validation. The survey had 2 sections, the first one briefly explaining the why and for what of the completion of this survey and the evaluation method which will be conducted according to the Likert scale [12], a second section where the questions were presented in accordance with the 4 categories that are to be validated: completeness, suitability, ease of use and ease of learning.

With the evaluation of the experts, the results of the validation of the proposed guidelines were obtained (See results Fig. 1), these experts provided suggestions for a better interpretation and greater impact of the guidelines on their use, some of the most outstanding opinions by categories were the following:

Fig. 1.
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Expert evaluation results

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Completeness:

  • To include an additional section that refers to when a guideline is violated

  • To improve writing and synthesize descriptions in some cases

Suitability:

  • No specific guidelines for learning mathematics are identified in children between 6 and 7 years old (only guideline 36 is found)

  • There are some guidelines that are generic, even heuristics such as Nielsen’s have been included, so they must be filtered and specified more in the context of children and mathematics

Easy to use:

  • To define a tool (guide) that facilitates the use of the guidelines, where it is determined when and how to use each guideline

  • To define a flow chart that helps to better understand the process for creating the application with the association of each guideline

Ease of learning:

  • The guidelines are written for a non-developer end user, it is necessary to use a more specific and technical language, to make it suitable and easier to use

  • The application steps are defined as recommendations, specific steps must be defined, in addition to including numbering, determining whether or not each step is mandatory, and the order in which they should be applied.

4.1 Analysis of the Results

According to the experts’ perception, it can be said that the guidelines contain the necessary elements to affirm that they are completeness, given that more than 80% of the respondents agree with this. In addition, it can be said that they are easy of learning, since more than 70% of respondents agree with this because they structurally contain the necessary elements and these are mostly well described.

Nevertheless, since more than 40% of respondent’s state that the guidelines do not consider appropriate information, it can be said that they are moderately suitable, this because all the guidelines must be based on the context of the children, mathematics and defined for the design of mobile applications specifically and some are not subject to this, they are very general guidelines that do not differentiate any context. In addition, it can be considered, where according to the experts’ perception, 50% of them determine that the guidelines are not easy to use because they are too extensive, the steps are not clear to apply and the examples presented, in some cases, they do not correspond to the use in the specific context and do not give a guide for its correct application.

These results on suitability and ease of use, according to the analysis carried out, is due to the fact that it is a first version of the guidelines, guidelines that were initially created based on literature review and surveys of teachers in the area, which showed that It was not enough and it was necessary to emphasize more in the context and to generate, in addition to new more specific guidelines for said context, a way to make them easier to use and understand.

4.2 Solutions for Problems Found by Experts

According to the results obtained by the evaluation of experts and their respective analyses, it was possible to determine the following proposed solutions to improve these results and be applied in a later stage of the guidelines, in such a way that they achieve the objective for which they were created.

Easy to use:

To solve a little the difficulty of the correct use of the guidelines since they are extensive, it aims to develop a guide to show the developer an optimal way to use it in the correct order and in the appropriate way, this guide can be handled graphically or in writing.

Suitability:

As most of the guidelines are focused on a more general context, it aims to focus the examples of use to our context (mathematics) and categorize them by parts, since every application needs general guidelines, in this way they are optimized both for our context as for the general context.

Ease of learning:

To solve the deficiencies found in this category, the steps of the application will be listed, written in a better way that shows how to do it by yourself, but not how it could be done, thus showing a step by step, it also will show, what steps are required and which are not.

5 Conclusions and Future Work

This paper presents the first version of a set of usability guidelines for the design of interfaces in interactive mobile applications in the context of learning mathematics in children between 6–7 years old, which were constructed based on guidelines found in the literature review, context analysis, and children’s needs.

The validation with experts allowed us to identify elements to improve the content, the structure, the form of presentation, the description of the guidelines, and their semantics. According to the expert opinion, it is determined that the guidelines were complete, easy to learn, moderately easy to use, and moderately suitable. Therefore, it is necessary to define in their description a set of elements that facilitate its use and adapt the existing elements to the specific context to improve its suitability.

From the comments obtained by the experts, it was possible to determine as possible improvements for the following stages of the investigation, the creation of a tool, which could be considered to have a guide (that determines the step by step of the design of the interfaces in the specific context and for each step which guideline to use) and a flow chart that graphically shows this process, and thus facilitate its use, in addition to the generation of a light version, that is, a new version of the guidelines that only has the identifier, name, category, and description, and apart from having the complement of the guidelines, which contains the application steps and the examples to be used, this in order to access the complement only when necessary and thus not be so extensive for its access.

As future work, the analysis and subsequent application of the suggestions made by the experts should be carried out, in order to generate a more complete version of the guidelines that must subsequently be validated in a real context, initially creating a functional prototype, using the guidelines and in this way, their application will be evaluated in the context for which they were designed, allowing the validation of useful aspects for their definition and subsequent use.