The PBL framework encourages collaboration with development partners when they have PBOs that pursue similar expected outcomes to those of CDB.  CDB seeks to harmonize appraisal, supervision and monitoring around a common policy matrix. In circumstances where CDB resources will not be sufficient to close the financing gap, staff will either appraise a PBO request as part of a joint operation with other development partners or consult closely with strategic partners to help mobilize resources. Staff are required to assess the adequacy of the macroeconomic framework for the conduct of a PBO.  The views of the IMF, the existence of an IMF program, or an Article IV assessment, are important ingredients in the appraisal. In the absence of an IMF program or Article IV assessment in the preceding 18 months, an assessment letter of the macroeconomic framework is requested. In the case of the UK Overseas Territories, a letter of approval from the requisite United Kingdom (UK) authority is sought.