  Observations show that nearly all star clusters and stellar populations
contain blue straggler stars (BSs). BSs in a cluster can significantly enhance
the integrated spectrum of the host population, preferentially at short
wavelengths, and render it much bluer in photometric colours. Current
theoretical simple stellar population (SSP) models constructed within the
traditional framework of single and binary stellar evolution cannot fully
account for the impact of these objects on the integrated spectral properties
of stellar populations. Using conventional SSP models without taking into
account BS contributions may significantly underestimate a cluster's age and/or
metallicity, simply because one has to balance the observed bluer colours (or a
bluer spectrum) with a younger age and/or a lower metallicity. Therefore,
inclusion of BS contributions in SSP models is an important and necessary
improvement for population synthesis and its applications. Here, we present a
new set of SSP models, which include BS contributions based on our analysis of
individual star clusters. The models cover the wavelength range from 91~{\AA}
to 160~$\mu$m, ages from 0.1 to 20 Gyr and metallicities $Z=0.0004, 0.004,
0.008, 0.02$ (solar) and 0.05. We use the observed integrated spectra of
several Magellanic Cloud star clusters to cross-check and validate our models.
The results show that the age predictions from our models are closer to those
from isochrone fitting in the clusters' colour-magnitude diagrams compared to
age predictions based on standard SSP models.
