[Retracted] M&A Short-Term Performance Based on Elman Neural Network Model: Evidence from 2006 to 2019 in China

Table 7

Comparison of advantages and disadvantages of five AR models.

Model	Market adjustment method	Market model	Unary nonlinearity	Unary polynomial	Elman model
Advantage	Easy calculation	Simple calculation with theoretical basis	Simple calculation	Infinite fitting can be realized theoretically by increasing the order	Can solve complicated nonlinear causality problem
Disadvantage	Lack of theoretical basis	Difficult to pass equation parameters’ significance test	Difficult to pass equation parameters’ significance test	Low-order: Poor fitting; high-order: Poor predictive ability	The program is complicated; the output layer information is underutilized
Innovation attempt	None	Take maximum correlation coefficient’s interval as observation period; eliminate the outliers	Selecting the best observation period by step progressive method; eliminate the outliers	Selecting the best observation period by the step progressive method; comparison of low-order and high-order fitting/prediction results	Keep the observation period as much as possible; comparison of closing price and yield rate as input information