Data collection tools

There are several standard tools for data collection for prospective and retrospective studies, as well as studies that are or are not subject to the WMO. This applies both to data collection on study participants by researchers and self-reported data submitted by study participants via web surveys. There is also a tool for monitoring study progress and an online randomization tool.

Available tools

Castor EDC is a suitable platform for building study databases for studies that are subject to the WMO, but it is also excellent for non-WMO studies.

If you build your eCRF pages/study database in Castor EDC, you can have study participants complete surveys online and view the results from your own Castor account. The survey module in Castor EDC lets you send out surveys to a predefined group of respondents, according to a fixed schedule, making it a suitable tool for most studies.

LimeSurvey and Survalyzer can be used to build more advanced surveys.

Researchers can design their own Castor, LimeSurvey and Survalyzer surveys, but can also outsource this for a fee. The costs will be billed to the project, and RDM will always create a quote first. You can also purchase a fixed number of support hours for assistance during the design process and for a final database review.

LDOT is a tool for managing the personal information of study participants and monitoring study progress.

Testing a study database

If your study is subject to the WMO, remember that the study will have to be tested by an independent reviewer, in addition to the user acceptance test that the study team itself has to perform (and document). More information about the main data collection tools can be found on the corresponding pages.

The RDM helpdesk can help you select one of these standard tools and suggest alternative solutions, as well as designing and building interactions with other systems.

Requirements for data collection tools

It is not allowed to enter data straight into programs like Excel and SPSS during the data collection process! These programs do not meet the requirements for research involving human subjects, e.g. because they lack validation features, audit trails and a system for managing roles and permissions.

If a data collection tool is hosted by Amsterdam UMC or an Amsterdam UMC partner (e.g. SURF, Lygature) then the appropriate licenses and Processor Agreements are in place. If you wish to use another data collection tool, you must discuss this with the Data Protection Officer first (e.g. for DPIA, BIV classification and a Processor Agreement). Please contact the helpdesk to verify whether an institution or company is an Amsterdam UMC partner.

Castor EDC

Castor EDC (Electronic Data Capture) is an easy-to-use web-based tool for building electronic Case Report Forms (eCRFs). Castor EDC is ICH-GCP and ISO 27001 certified. So this platform helps meeting the requirements for electronic data collection in studies subject to the WMO. Make sure that your study database complies with ICH-GCP and the GDPR by enabling the correct settings <Link follows>. It is also important to request medication data and (S)AEs correctly (you can find example forms on the Castor Form Exchange).

Castor EDC is also a valuable tool for data collection in studies that are not subject to the WMO. In addition to serving as an eCRF system or a platform for data entry of paper CRFs, Castor EDC also allows you to send web surveys (for complex surveys, you can also use LimeSurvey or Survalyzer) and randomize study participants. A link between Castor and Epic (via the RDP) has been made available, which makes it possible to upload data to an eCRF straight from the source. Castor EDC can also be linked to the LDOT study monitoring tool.

Training course

Castor EDC is a user-friendly tool and most users only need to follow a few brief tutorials or a quick training course before they are able to design their own database. For more information about training courses and support, see the internal tutorials of the Castor Academy.

Key features of Castor EDC

  • ICH E6 (R2) GCP / FDA 21 CFR Part 11 compliant platform
  • GCP features:

    • All actions are recorded in an audit trail
    • Locking and unlocking features
    • Digital signing of CRFs
  • Track reasons for changes (enable GCP option ‘Confirm Changes’)
  • ISO 27001 certified: complies with requirements on access and back-ups

    • Prevents unauthorized access to data
    • Data are backed up regularly, and back-ups are maintained
    • Assign different user roles with corresponding permissions
  • Suitable for multi-center studies
  • Various validation options (min-max values, integrated calculations, etc.)
  • Source Data Verification capabilities (e.g. placing queries and confirming correct entries)
  • Encryption of privacy-sensitive information
  • Supports stratified block randomization with various alternating block sizes (for complex randomizations, please consult the statistics helpdesk)
  • Research data deblinding
  • Library of existing CRF pages, including forms approved by Amsterdam UMC
  • Web survey capabilities
  • Data import capabilities from Excel
  • Data can be easily exported from Castor to e.g. CSV, Excel, SPSS

Check the Castor website for more information.

At VUmc, Castor and Epic are linked via the Research Data Platform, eliminating the need to manually copy research data from Epic only to enter them into an eCRF in Castor. This saves time and ensures higher-quality data sets by eliminating copying and typing errors.

Initially, the link will only be available for GLIMS lab data, but other data categories, such as medication, will be added in the future. The work instruction below describes how the link works. For more information on using the link and for support, please contact the RDM helpdesk.


Amsterdam UMC has a license to use Castor EDC for non-commercial studies in which Amsterdam UMC is the coordinating center. You can request an account to build your own study in Castor EDC via: data castor EDC register. Please use your Amsterdam UMC email address. There is a free online tutorial on building your own study: academy castor EDC. We also organize training sessions for new and advanced users in collaboration with Castor EDC.

Please note. To use Castor EDC at the institutional rate, you have to enter the sponsor’s billing code when your study goes live. For the billing code, contact the RDM Helpdesk

Support from RDM

We provide advice on the application, required documentation and use of Castor. We can also review a study built in Castor free of charge before it goes live. We can also build studies in Castor EDC for you for a fee, for which a quote will be prepared following an intake session. For support, contact RDM.

Online surveys: Survalyzer

You can use Survalyzer, formerly known as Netquestionnaires, to make web surveys. This program has much more comprehensive features for designing and sending web surveys than Castor EDC, but it is not an (e)CRF system. For eCRF features, use Castor EDC.

You can use ReadEmail, another database program, to fully automatically send surveys at various measurement occasions, derived from the individual T0 date of every participant. This program can also automatically send reminders when a survey deadline has passed.

Online surveys: LimeSurvey

For more advanced survey types or invitation methods, you can use LimeSurvey, which lets patients/respondents complete surveys online and anonymously. If the entered data are not subsequently changed by the researcher (demonstrably and documented), this program may also be used in studies subject to the WMO by way of exception.

KLIK PROM portal

The KLIK PROM portal was developed at Amsterdam UMC. The primary purpose of this tool is to discuss Patient-Reported Outcomes (PROMs: questionnaires) in the consulting room. KLIK PROM can also be used as a data collection tool, especially when using surveys completed by patients. The KLIK team, consisting of PROM experts, can provide input and advice on the choice of surveys and the constructs to be measured, if required.

For applications, costs and more information, please contact the KLIK Amsterdam UMC PROM expert team. For more general advice on tools, please contact RDM.


Recording audio

Safely recording and processing audio for scientific research

Several tools for safely recording and processing of confidential audio for scientific research have recently been made available to Amsterdam UMC researchers, consisting of connected recording tools (dictaphone or app) and special software for processing the (encrypted) audio files.

For more information and to request the various instruments, see the service description in the Service Catalogue of ServiceNow: Calls and requests - Service Portal (

Interview tool: Blaise

You can use Blaise to conduct face-to-face (via a laptop) or phone interviews for studies that are not subject to the WMO. This advanced program lets you provide extensive instructions and explanations to guide the interviewer.

Guiding and monitoring study progress: LDOT

You can use the web-based program LDOT to manage the personal information of study participants and monitor study progress, e.g. to determine which study participants should be approached for a (follow-up) measurement. LDOT is not used to capture study data, but only tracks contact and process data, such as the dates on which a certain event took place and what follow-up actions were linked to it. LDOT can communicate with data collection tools such as Castor EDC, so that relevant data do not need to be entered twice.