Potential data sources (ranking):

1. Certification
   1. Insb. applicable for the building blocks tour operator, accommodation and destination agency
   2. Source: Database (gti or similar)
2. External data sources
   1. Applicable for indicators for which external (online) sources are available
   2. Source: Databases (atmosfair emission calculator, DJSI etc.)
3. Light certification by external audit
   1. Applicable for indicators on service providers who do not have comprehensive certification
   2. Source: Established certification provider carries out a compressed audit of the corresponding service provider and makes the results available
4. Entry in database by original source
   1. Applicable for indicators on subordinate service providers (e.g. accommodation, catering establishments, partner agency, tour guide or activity provider)
   2. Source: Entry in database based on self-disclosure of the service provider (at gti or similar). Impulse to the entry by the tour operator
   3. Objective: Consecutive expansion of the database
5. Self-disclosure
   1. Applicable to indicators for which no objective data are available
   2. Source: Tour operator enters the data himself or passes on the questions to the corresponding service provider (on site)

In the last instance, the organizer must turn the corresponding self-reports into indicators without objective sources. However, every effort is made in the process to collect the data from other sources or to motivate the service providers (on site) to enter directly.

The verification mechanisms used to ensure credibility are:

1. Customer feedback (4-5 questions in the organizer’s main questionnaire + 10-15 questions in voluntary additional survey)
2. Random verification of self-disclosure
3. The evaluation of a building block by a certificate receives a higher point than the sum of all indicators in the context of self-disclosure, since an independent validation of the results by third parties increases the quality of the statement

A complete review of the information by the tour operator is not affordable and is therefore not intended within the framework of this project.

In the long term, the aim is to gradually replace the indicators with objective sources.

For demonstrable false statements by tour operators, appropriate sanctions are set.