“…Such use is generally found to be concentrated among users of less-effective methods, although lower levels of combining less- and highly effective methods were also identified in these studies (Frost et al, 2007b ; Gray et al, 1999 ; Jones et al, 2014 ; Parr & Siedlecky, 2007 ; Sato & Iwasawa, 2006 ; Spinelli et al, 2000 ; Toulemon & Leridon, 1998 ; Whittaker et al, 2010 ). There is some evidence that, in the U.S., both multiple method use and use of less-effective methods are higher among members of disadvantaged subgroups: young people and racial and ethnic minorities (Brown et al, 2011 ; Frost & Darroch, 2008 ; Guzman et al, 2013 ; Mosher & Jones, 2010 ; Sznitman et al, 2009 ). Reflecting this, in-depth research on combination and less-effective method use has either has been carried out among specific subgroups (rather than examining all women), or has focused on use of specific methods, rather than looking at a woman’s full range of contraceptive methods (Arevalo et al, 2004 ; Brown et al, 2011 ; Gray et al, 1999 ; Guzman et al, 2013 ; Horner et al, 2009 ; Sinai & Jennings, 2014 ; Sznitman et al, 2009 ; Whittaker et al, 2010 ).…”