“…In the literature, alternative techniques and methods have been introduced to perform this information reduction: targeting indicators with thresholding rules (Bai and Ng, 2008, Schumacher, 2010, Bulligan et al, 2012, and Kim and Swanson, 2013, estimating weighted principal components and preselecting indicators with rules that eliminate irrelevant information Ng, 2006, andCaggiano et al, 2011), estimating factors under a sparse prior (e.g. Kaufmann and Schumacher, 2013), and selecting one "representative" indicator of each category in which the large panel can be classified (Alvarez et al, 2012).…”