How many episodes were titled "identity crisis"?
CREATE TABLE "table1_10715317_2" (
  "no_in_series" real,
  "no_in_season" real,
  "title" text,
  "directed_by" text,
  "written_by" text,
  "original_air_date" text,
  "u_s_viewers_millions" text
);
SELECT COUNT("directed_by") FROM "table1_10715317_2" WHERE "title"='\"Identity Crisis\"';