TY - JOUR TI - Portfolio Inputs Selection from Imprecise Training Data AU - Raudys, Sarunas AU - Raudys, Aistis AU - Biziuleviciene, Gene AU - Pabarskaite, Zidrina TI - Portfolio Inputs Selection from Imprecise Training Data AB - This paper explores very acute problem of portfolio secondary overfitting. We examined the financial portfolio inputs random selection optimization model and derived the equation to calculate the mean Sharpe ratio in dependence of the number of portfolio inputs, the sample size L used to estimate Sharpe ratios of each particular subset of inputs and the number of times the portfolio inputs were generated randomly. It was demonstrated that with the increase in portfolio complexity, and complexity of optimization procedure we can observe the over-fitting phenomena. Theoretically based conclusions were confirmed by experiments with artificial and real world 60,000-dimensional 12 years financial data. VL - 2016 IS - Volume 25 PY - 2017 SN - 1732-3916 C1 - 2083-8476 SP - 177 EP - 188 DO - 10.4467/20838476SI.16.014.6195 UR - https://ejournals.eu/en/journal/schedae-informaticae/article/portfolio-inputs-selection-from-imprecise-training-data KW - sample size KW - variable selection KW - Complexity KW - financial portfolio KW - overfitting