For the last two decades, we have seen a huge development of modern cosmology based on observations such as the cosmic microwave background (CMB), type Ia supernovae, and baryonic acoustic oscillations (BAO). These pieces of observational evidence have led us to a great deal of agreement on the ΛCDM cosmological model, a model for which we have tight constraints on cosmological parameters. 

 On the other hand, this advancement in cosmology relies on the cosmological principle: the universe is isotropic and homogenous on large scales. Testing these fundamental assumptions is crucial and, in fact, extensive testing will soon become possible given the planned observations ahead. 

 Measuring dipolar modulation is an effective method to test the statistical isotropy due to the fact that dipolar modulation corresponds the largest anisotropy of the sky. In CMB experiments, dipolar modulation was well measured which mainly originated from our solar system’s motion relative to the CMB rest frame. However, we have not yet acquired consistent measurements of the kinematic dipolar modulation in large-scale structure (LSS), as they require large sky coverage and a number of well-identified objects.

 During the talk, I will introduce the measurement of dipolar modulation in LSS as a test of statistical isotropy. The talk will be based on two published papers. In the first paper (arXiv:1406.1187), dipolar modulation caused by local structure, was measured in number counts of WISE-2MASS sources. The second paper (arXiv:1509.05374) investigated requirements for detection of kinematic dipolar modulation in future surveys.