The assessment of funding needed by developing-country Parties and Parties with economies in transition to implement the Stockholm Convention is conducted quadrennially. Parties and others are invited to provide the relevant information required to undertake the assessment of funding needs for consideration by the Conference of the Parties. For the collection of relevant information, the Parties are requested to fill out the questionnaire prepared according to the terms of reference set out by the Conference of the Parties. A team of independent experts undertakes a full assessment of the funding necessary and available for the implementation of the Convention forward-looking for a four-year period, based on, among other things, the experience in using and lessons learned from the methodology and available data gained from the preliminary assessments of funding needs for the previous periods for consideration by the COP.