public static double wordDifference(Map<String, Integer> t1, Map<String, Integer> t2) {
		// construct total word counts
		int totes1 = 0;
		int totes2 = 0;
		for (String s : t1.keySet()) {
			totes1 += t1.get(s);
		}
		for (String s : t2.keySet()) {
			totes2 += t2.get(s);
		}
		// construct return value for first author
		double val = 0;
		// goes through everything in t1
		for (String s : t1.keySet()) {
			Integer temp = t2.get(s); //we cannot use int here!  get may return null
			if (temp == null) {
				temp = 0;
			}
			double freq1 = ((double) t1.get(s))/totes1;
			double freq2 = ((double) temp)/totes2;
			val += Math.abs(freq1 - freq2);
		}
		// goes through everything in t2 that is NOT in t1
		for (String s : t2.keySet()) {
			if (!t1.containsKey(s)) {
				val += ((double) t2.get(s))/totes2;
			}
		}

		return val;
	}