  It is widely recognised that filament disappearances or eruptions are
frequently associated with Coronal Mass Ejections (CMEs). Since CMEs are a
major source of disturbances of the space environment surrounding the Earth, it
is important to investigate these associations in detail for the better
prediction of CME occurrence. However, the proportion of filament
disappearances associated with CMEs is under debate. The estimates range from
$\sim$10% to $\sim$90% and could be affected by the manners to select the
events. In this study, we aim to reveal what parameters control the association
between filament eruptions and CMEs. We analysed the relationships between CME
associations and the physical parameters of filaments including their length,
maximum ascending velocity, and direction of eruptions using 28 events of
filament eruptions observed in H$\alpha$. We found that the product of the
maximum radial velocity and the filament length is well correlated with the CME
occurrence. If the product is larger than 8.0$\times$10$^{6}$ km$^{2}$
s$^{-1}$, the filament will become a CME with a probability of 93%, and if the
product is smaller than this value, it will not become a CME with a probability
of 100%. We suggest a kinetic-energy threshold above which filament eruptions
are associated with CMEs. Our findings also suggest the importance of measuring
the velocity vector of filament eruption in three-dimensional space for the
better prediction of CME occurrence.
