Reliable national accounts are essential for proper economic analyses and informed policymaking by national authorities as well as other stakeholders. Nevertheless, in many countries, national accounts statistics are subject to serious shortcomings, which are often manifested as overestimated growth rates. In cases where official data are not adequate for surveillance, IMF staff compile alternative estimates by applying various forecasting methods. This study proposes a more holistic, bottom-up approach, which is based on the compilation of GDP by the expenditure method with limited source data. The study also discusses the case of Turkmenistan, where this method was implemented in practice.