NPR only has so much content, even if it broadcasts twenty-four hours per day. We can call this total content, TC for short. Now, if NPR has more and more con

NPR only has so much content, even if it broadcasts twenty-four hours per day. We can call this total content, TC for short. Now, if NPR has more and more content about "progressive political ideology" (PPIC), there would therefore be less content about any other topical content (AOTC). If PPIC + AOTC = TC, and NPR increases PPIC as TC is held constant, means that AOTC must decrease. I hope that clears it up for you.