Introduction

1. Towards a Quantitative Concession‐Based Classification Method of Negotiation StrategiesTim Baarslag, KoenHindriks, CatholijnJonkerMan-Machine Interaction GroupDepartment of MediamaticsFaculty Electrical Engineering, Mathematics and Computer Science Delft University of Technology

2. Introduction In order to successfully reach an agreement in a bilateral negotiation, both parties rely on each other to make concessions. After the opening offers, a negotiator has to decide how much to concede next. Many current negotiation strategies are characterized by their concession making strategy. Making Concessions in a Negotiation

3. Introduction For instance: time-dependent tactics, Hardliner, Random Walker. Negotiation Strategies from S.S.Fatima et al. (2002)

4. Introduction We also consider agents from The Automated Negotiating Agent Competition (ANAC) 2010 held at the AAMAS conference. Negotiation Strategies

5. Introduction We can observe that some strategies play very competitively: Hardliner, Boulware, But what does ‘competitive play’ mean (and how does it affect the outcome)? Making Concessions in a Negotiation

6. Introduction Negotiators can exhibit a mixture of cooperative or competitive behavior, mainly depending on the type of opponent. The choice for when and how to make concessions depends in large part on the opponent. Making Concessions in a Negotiation

7. Introduction Making Concessions in a Negotiation

8. Introduction The goal is to define a formal, quantitative procedure for classifying agents into one of the four categories. We present a new classification method for negotiation strategies, based on their pattern of concession making against different kinds of opponents. We introduce notion of concession rate (CR) which measures the cooperativeness of an agent. We then apply this technique to classify some well-known negotiating strategies, including the agents of ANAC 2010. Concession Rate

9. Concession Rate Concession rate (CR) quantifies the total amount an agent has conceded towards the opponent during a negotiation. The concession rate of an agent A is a normalized measure CRA∈ [0,1] If CRA = 0, then A did not concede at all during the negotiation, while CRA = 1 means that player A yielded completely to the opponent. Definition

10. Concession Rate It is not enough to consider the utility of the agreement as a measure for the concession rate. We define the concession rate in terms of the minimum utility m a negotiator has demanded during the negotiation. Definition

11. Concession Rate t = 0.1 Illustration

12. Concession Rate t = 0.1 Illustration 0.1 0.8

13. Concession Rate t = 0.1 t = 0.2 Illustration

14. Concession Rate t = 0.1 t = 0.2 t = 0.3 Illustration

15. Concession Rate t = 0.1 t = 0.2 t = 0.3 t = 0.4 Illustration

16. Concession Rate t = 0.1 t = 0.2 t = 0.3 t = 0.4 t = 0.5 Illustration

17. Concession Rate t = 0.1 t = 0.2 t = 0.3 t = 0.4 t = 0.5 t = 0.6 Illustration

18. Concession Rate t = 0.1 t = 0.2 t = 0.3 t = 0.4 t = 0.5 t = 0.6 t = 0.7 Illustration

19. Experiments Measuring the CR of different agents Agents Two opponents Agent K A cooperative strategy Yushu vs Boulware IAMhaggler A competitive strategy … What to negotiate about?

20. Experiments Negotiation scenarios • Negotiation strategies have to be assessed on negotiation domains with different characteristics. • We picked two domains from ANAC 2010: • Buyer–seller business negotiation between Itex Manufacturing (producer) and Cypress Cycles (builder). (Kersten et al., 2003) • Trade negotiation between England and Zimbabwe on an agreement on tobacco control. (Lin et al., 2008) • Agents play both sides of every scenario.

21. Experiments Negotiation scenarios • Two scenarios with a good spread of negotiation characteristics.

22. Experiments We let the agents negotiate against both a very cooperative and a very competitive opponent. The opponent tactics that we use to measure concession rates are simple, non-adaptive negotiation tactics. For the competitive opponent, we chose Hardliner, which simply makes a bid of maximum utility for itself and never concedes. For the cooperative opponent, we selected Conceder Linear, which linearly reduces its demanded utility. Opponent Strategies

23. Results

24. Results – Extreme Cases Random Walker will make arbitrary concessions given enough time. Hardliner and Random Walker are at the opposite sides of the spectrum. By definition Hardliner has CR = 0 against both Hardliner and Conceder.

25. Results – Time Dependent Tactics e = 0.2 e = 2 e = 1

26. Results – Time Dependent Tactics Bigger e, bigger concessions, bigger CR

27. Results – Time Dependent Tactics Smaller e, smaller concessions, smaller CR

28. Results - Clustering

29. Results - Clustering

30. Results - Clustering Most successful strategies of ANAC are Competitors

31. Results - Clustering

32. Conclusion Making concessions during a negotiation is vital for getting an agreement. We defined the concept of concession rate, which measures an agent’s willingness to concede against different opponents. This gives insight into the strategy space of well-known negotiation tactics. We established our method can be useful to cluster strategy types, and early results indicate successful agents should be Competitors.

33. Conclusion The acceptance strategy is an important part of a negotiator’s strategy that also highly influences the outcome of a negotiation. Classify and analyze agents from ANAC 2011*. Future Work *Joint work together with University of Southampton, Bar-IlanUniversity, and Nagoya Institute of Technology

34. Conclusion Classify and analyze ANAC 2011 agents in upcoming AIJ paper Future Work Most successful strategies of ANAC 2011