Effect of inhomogeneous particle-size distribution on the effective LSPR peak position and broadening of the optical spectra of metal nanoislands thin films has been examined using Modified-Yamaguchi's model (MYM). Effective dielectric constants (epsilon(1), epsilon(2)) of the pulsed laser deposited metallic nanoislands thin films has been extracted using Spectroscopic Ellipsometer (SE) to provide an insight of laser ablation wavelength dependent growth kinetic of the films. Simultaneous fitting of polarized spectra along with psi and delta parameters strengthens the applicability of applied set of oscillators. Origin of negligible film roughness in ellipsometric results has been attributed to the plasmonic averaging of the spectra. Effective polarizability and the phase difference between transmitted and scattered wave have been calculated using epsilon(1) and epsilon(2). Present study shows the way of selecting laser ablation wavelength to deposit Ag nanoislands thin films as per the requirement of sensors and photovoltaic solar cells. A practical use of SE has been reported unlike previous studies which are limited to the measurement of dielectric constants only. (C) 2018 Elsevier B.V. All rights reserved.