9 Naming of files and variables

The purpose of this section is to ensure we follow a consistent and systematic naming and description of our research data. A uniform structure makes it easier to identify, understand, and analyse data across visits and preparatory activities. It also supports correct workflow configuration and contributes to data quality and traceability in the study.

All names and descriptions must be written in UK English.

9.1 Files

In general, a file uploaded either to REDCap or directly to GenomeDK should contain:

The ID of the participant
The origin of the data (often a sensor or a scanner)
Which visit the data originates from
Which repeat of the test it shows (where relevant)

For example:

3_v4_dxa.csv: Participant 3, visit 4, DXA scanning
3_v4-5_finapres.csv: Participant 3, visit 4, run number 5 of the finapres scanning.

Our naming rules

Use an underscore (_) to separate individual items (who, when, what).
Use a hyphen (-) to indicate multiple measurements at the same visit.

9.2 Variables

This section assumes REDCap is used for data collection. Instruments (forms) contain fields for each variable, with both a field name and a field annotation for descriptions.

The name of the forms (instruments) must indicate whether:

The form is used for preparation before a participant’s visit, or
The form is used during a visit to record participant data.

All variable names and descriptions must indicate the visit to which they belong. This should be specified:

At the end of the variable name (e.g., _v1, _v2, etc.), or
In the description (e.g., Visit X).

Tip

In REDCap you can use the Action Tag / Field Annotation section (currently situated at the bottom left) to capture the variable descriptions.

9.2.1 General requirements for all visits

Each visit must begin by recording:

Date of the visit
Initials for the project visit
Whether the participant is identified by name and CPR
Whether a relative is present
Who the relative is

It is important to use the same variable names for these items, only changing the visit number as appropriate.

Each visit must end with:

A description of any points of attention prior to the next visit (if any)
A summary and general comments on the visit

Tip

In REDCap these can be copied from one visit to another, but ensure that for instance v1 / visit 1 is updated to the correct visit number.

9.2.2 Distinction between visits and preparations

It is important to distinguish between:

Instruments/variables belonging to the actual visit
Instruments/variables related to preparations for the visit (These are mainly for internal workflows and practicalities)

9.2.3 Naming conventions

Variables related to preparations for a visit must use the following format:

[descriptive_name]_wfvX Example: bloodsamples_wfv1

(where wfvX stands for workflow visit X)
Description for preparations:

Workflow. Preparations for visit X. Example: Workflow. Preparations for visit 1
Description for workflows during a visit:

Workflow. Visit X. Example: Workflow. Visit 1

9.3 Describing variables

Action tags should follow a streamlined description, ideally including the following elements:

Who the value belongs to (optional). Used only if it is not the participant (e.g., staff member)
What is being measured (mandatory). Provide a short and precise description of the measurement
Unit of measurement (if relevant), e.g., kg, mmol/L, minutes
Where or how it was measured (if possible), e.g., “measured with digital scale”
Visit number (mandatory). Used to distinguish between repeated measurements and to place the variable on the study timeline

Example:

Participant’s weight in kilograms, measured wearing light clothing using a digital scale. Measured to the nearest 0.1 kg. Visit 1.

9.4 Quick reference

Category	Rule	Example
File naming	`[participantID]_v[visit]-[repeat]_[dataorigin].ext`	`3_v4_dxa.csv` or `3_v4-5_finapres.csv`
Variable naming	`[descriptive_name]_vX` for visit data, `[descriptive_name]_wfvX` for workflow	`weight_v1` or `bloodsamples_wfv1`
Visit description	Always include visit number in description	`Visit 1`
Workflow description	Preparations: “Workflow. Preparations for visit X”. During visit: “Workflow. Visit X”	“Workflow. Preparations for visit 1” or “Workflow. Visit 1”
Variable description elements	Who (optional), what (mandatory), unit (if relevant), where or how (if possible), visit (mandatory)	“Participant’s weight in kilograms, measured wearing light clothing using a digital scale. Measured to the nearest 0.1 kg. Visit 1.”