Different values for the real-space correlation length r₀ against redshift for RLQs and RQQs from SDSS DR5 (purple and gray downward triangles, Shen et al. 2009), optical quasars (gray circles, Croom et al. 2005; Ross et al. 2009; Eftekharzadeh et al. 2015), radio galaxies (dark green squares, Peacock & Nicholson 1991; Magliocchetti et al. 2004; Wake et al. 2008; Fine et al. 2011; Lindsay et al. 2014b), and FSRQs (orange star, Allevato et al. 2014a). The r₀ values for RLQ and RRQ in our sample are represented by red and gray upward triangles, respectively. For comparison, we show the r₀ values corresponding to r₀ = [11.8, 7.1] h^-1 Mpc (dashed lines). The results from Lindsay et al. (2014b) are derived assuming linear clustering.