Recruiting and 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;
  • Training protocol including requirements regarding intra- and inter-observer agreement;
  • Training sessions according to the training protocol.



  • 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).
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.
Research assistant:
  • 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:
  • 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. 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 (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. The data collectors need to be aware of (examples: protocol 1 protocol 2 protocol DOiT study).
For many studies it is important that the data are collected in an as standardised way as possible. This means that the interviews or test schedules need to be standardised. 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). 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.


Audit questions

  1. Has a qualification list been created for recruiting the data collectors?
  2. Have the data collectors been informed of the aim of the study and the tests/questionnaires?
  3. Have all the measurement/interview components been established in a protocol?
  4. Has a training protocol been established for the study?
  5. Have the data collectors been trained?
    1. If so, how and by whom?
  6. Are multiple data collectors involved in the study?
    1. If so, which measures have been taken to measure and reduce mutual variation?
  7. Have new data collectors been recruited during the data collection process?
    1. If so, who trained these data collectors?
    2. Which measures have been taken to measure and reduce mutual variation between the new data collectors?

V3.1: 20 Jan 2017: English translation of training protocol added
V3.0: 13 Oct 2016: Revision guideline
V2.0: 12 May 2015: Revision format
V1.3: 1 Jan 2010: Translation into English
V1.2: 8 Jul 2008: Minor textual modifications
V1.1: 19 Oct 2006: Reference to the quality handbook