public double getMRR() {
		if (this.predictionData.size() != 0 && this.realData.size() != 0) {
			double sum = 0.0;
			for (String val : this.realData) {
				int index = 0;
				if ((index = this.predictionData.indexOf(val)) != -1) {
					sum += (1.0 / (index + 1));
				} else {
					sum += 0.0;
				}
			}
			return sum / this.realData.size(); // TODO: correct?
		}
		return 0.0;
	}