Data validation

The data validation page has many different options for the user. Firstly, they need to check which validation type they want and after that input the upper and lower limit validation values.

Visibility To make it less complicated for the user, we only show the validation types they would need. For example, when the user has not chosen to input the child’s age we do not show the validation types relating to a child’s age.

Feedback The user will not be confused about the content of the page as we have made it as simple and concise as possible. The labels to set a upper and lower limit value for the outcome of the program are very clear.

AffordanceThe checkboxes and fields are all aligned with clear headings in a grid format so it easy for a user to understand which type of validation he/she is entering values for.

Consistency This page is consistent with the rest of the app as it uses the same color palette and fonts. Moreover, the method in which each validation type is set out is consistent to make it easier for the user.

Constraints There are a few constraints available on this page. Firstly, at least one validation type must always be chosen. This is due to the fact that this page will only show if the user has selected the validation option and therefore must input at least one validation method. Secondly, The app makes sure that the

upper limit is always greater than the lower limit for logical reasons. Lastly, if a validation type is selected the user must not leave neither the upper or lower limit blank, as these must always be specified.

Mapping All the screens in the app have an action bar at the top, which allows them to either go back to the previous screen or go to a help page.

Gender

Visibility and Affordance The gender page is very concise and simple. The user will see two radio buttons each one with a gender label clearly labeled next to it. The user will select the correct gender.

Feedback Whichever option is selected, it will be clearly shown to the user by putting a dot in the option selected.

ConsistencyThis page is consistent with the rest of the app as it uses the same color palette and fonts.

ConstraintsThe app will make sure one option is selected before the user can proceed to the next page. Also, it will not allow the user to make two selections as that would not make sense.

Mapping

All the screens in the app have an action bar at the top, which allows them to either go back to the previous screen or go to a help page.

Length and MUAC

Visibility The length label would change to “height” in the event that the user chose the “length or height” option and selected height. Another option that would affect these two screens is the “double data entry” option. If selected, the screen will show two entry fields in which the user will have to enter two measurements of length/height and MUAC (as shown in the picture on the right). If the option is not selected, the second field is hidden from the user as he/she will not be using it.

FeedbackThe screen is very simple. There is a number field underneath the labels and it is clear to the user where to input the values.

AffordanceWhen the user tries to insert a value, only a number keyboard will be shown. The user will then know that the input is expecting a number.

Consistency The length and MUAC pages are somewhat identical as their function is to take the user’s inputs for length and MUAC. Therefore, once the MUAC page has been used, the user will be familiar with the length page. This page is consistent with the rest of the app as it uses the same color palette and fonts.

Constraints The number fields in these two pages do not allow negative values to be entered, as it is not logical to have a negative length or MUAC. Moreover, no field can be left empty, as the information is important for the outcome of the app. If double data entry is selected, the difference between the two values must be less than or equal to 0.7 as per the double data entry rules of the MOYO chart. The values entered must also be within the limits specified by the MOYO chart. The upper and lower limits for length/height change in respect to boys and girls.

Mapping All the screens in the app have an action bar at the top, which allows them to either go back to the previous screen or go to a help page.