# Types of variables

Modified on Thu, 1 Sep, 2022 at 10:37 PM

All the variables are not the same! The number of days of hospitalization and the type of operation are slightly different. And that difference is important when it comes to statistics ...

## The 4 basic types

In EasyMedStat, there are 4 types of variables: list, yes-no, numeric and event.

#### List

You use it when you have a limited number of options for the answer.
For example, the type of operation could be for your series on the knee surgery one of: Meniscectomy, Total arthroplasty, Unicompartmental arthroplasty, ACL Ligamentoplasty, Osteotomy.

So you have 5 possible answers to the question: "What operation was performed on the patient ?". This is a "List" variable. In statistics, it is also called a discrete multinomial variable.

#### Yes-no

You use it when the answer to the question can only be yes or no. For example, Smoker: yes or no? Epilepsia: yes or no? This type of variable should be preferred over List variables whenever possible because it allows more statistical test power.

#### Numeric

Use it when the data is a number which can take any value (the number of possible values is not known before the study).
For example, the patients' weight could go from 40.0 kgs to 110.0 kgs but with many intermediary values: 67.3, 81.2, ...
In this case, it is better to use the Numeric type. In statistics, it is also called a continuous variable.

#### Event

You use this type when you want to track an event that could happen to a patient.

For example, the re-intervention date or the date of a complication could be a noticeable event you would like to track. This is the only type of variable that allows making survival analysis (Kaplan-Meier, …)

## How to collect free text?

To define a free text input, choose a "List" variable and choose the option "The user can always enter free text".

A simple text input will then be displayed in the form.

## You may also be looking for...

The following variables are currently not available:

• Checkboxes and multiple selectors: these types of inputs are not supported because they may lead to data inconsistency. We recommend you avoid this kind of question. Indeed, if a checkbox is not clicked, you can never know if this is because the user has not answered (NC) or because the answer is "No". Therefore, monitoring can quickly become problematic.
• Times: you can not yet collect "times" like "00:32" with a specific input. You can however define a free text input or a List input as a workaround.