Recruiting & training data collectors


To secure accurate data collection by recruiting and training data collectors.

  • Qualification list for recruiting data collectors;
  • Study protocol, including study goals and information about tests/questionnaires;
  • Standard operating procedures for data collection;
  • Training protocol including requirements regarding intra- and inter-observer agreement;
  • Training sessions according to the training protocol.
  • Delegation log of delegated tasks filled out and stored in Investigator Site File, & training log signed by trainer and trainees

Documentation as described under ‘Requirements’.


Executing researcher:

  • To set up the qualification list together with the project leader(s);
  • To appoint data collectors on the basis of a qualification list, drawn-up prior to recruitment;
  • To train data collectors in line with a training protocol, that has been set-up together with the project leader(s).
  • To check if a confidentiality agreement is signed
  • To create and fill out a training log and delegation log.

Project leaders:

  • To help the executing researcher with putting together the qualification list for the recruitment of the data collectors;
  • To ensure the executing researcher appoints data collectors on the basis of this qualification list;
  • To monitor the training provided by the executing researcher and completeness of logs.

Research assistant:

  • To sign the training log. With the signature the RA states to be adequately trained.
  • To accurately collect the data by following the protocol;
  • To ask for any help on time when things aren’t clear or when problems occur.
How To

A good data collector for scientific research needs to have a number of specific qualities that can be used as selection criteria when recruiting. These qualities may, of course, differ from study to study. It is good practice to create in advance a list of qualifications the data collector(s) need(s) to fulfil, for example:

  • Having a Good Clinical Practice certificate
  • Experience or affinity with data collection procedure (interviews, tests);
  • Experience or affinity with study population (patients and/or professionals);
  • Knowledge of, or experience with the research topic;
  • Experience with specific computer programmes;
  • Able to work accurately;
  • Able to work independently;
  • Have good communication skills;
  • Presentable;
  • Flexible;
  • Available for the whole study period;
  • Own car.

The data collectors need to be given sufficient background knowledge about the study and its procedures. They need to know how and why certain details are being collected (the ultimate aim and the specific information the test/questionnaire will provide). This knowledge can be acquired by reading the protocol and/or training protocol (where required). The necessary background information needs to be established in a comprehensive data collection protocol, including a description of all the measurement/interview components.

For many studies it is important that the data are collected in an as standardized way as possible. This means that the interviews or test schedules need to be standardized. The data collector needs to conduct the interview or present the test in exactly the same way each time (as little as possible intra-observer variation). Comprehensive instructions and interview / test training will be required for this. Where there are multiple data collectors, mutual differences will need to be measured and minimalized (as little as possible inter-observer variation). Comprehensive training will also be required for this.

To train the data collectors properly, it is important to create a training protocol (examples: protocol 1, protocol 2, protocol DOiT study – see under Download). before the start of the study. This protocol will include: the instructions to be provided, who is conducting the training and whether the training will be repeated during the data collection. It is also important to indicate at what stage the data collectors will have received sufficient training. Fixed guidelines can be drawn up for this by setting a specific threshold (for instance Cohen’s Kappa > 0.6 for inter-observer variation), or the requirement that the data collector meets the same level of measurements/observations as a gold standard or highly experienced data collector. If there are multiple data collectors active within the study, the inter-observer variation needs to be measured and minimalized through training.

New data collectors, starting during the data collection process, should be trained by the same individuals who provided the original training, and not by other data collectors.

After the training, it is important to verify that trainees feel adequately trained to collect data. A training log is created, documenting who was trained by whom, on which date and signed by both trainer and trainee. Also, the delegation log is filled out, stating which tasks are being delegated to the newly trained data collector.

Supervision is provided throughout the data collection period, to ensure that data is still being collected according to the protocol. Such supervision can for example be to sit in on an interview and provide feedback afterwards.

Appendices (under Download)

Example of training protocol (English)