PACK vs TEAM vs CHAIN Strength by Group size and Problem Difficulty.
# PACK to CHAIN to TEAM? The initial motivation for Teams, Packs and Chains was to provide substantive meaning for solutions to the problem of non-physical concatenation (RMT 9:2 432-433). Once posited, it is intriguing to ask how Teams, Packs and Chains relate and progress. A Pack succeeds when any member succeeds. It works best when everyone tries something different -- like hunting for food in the Artic. Any new project begins as Pack searching, abduction, intuitive leaps, wild hypotheses, anything goes,brainstorming. The only agreement is in what the core problem most likely,probably, might be. A Chain relies on solidarity. It works when everyone is in lock step, but it fails when any member stumbles -- like a link of a chain breaking. As projects develop,as possibilities are separately, accidentally encountered, the need for coordination emerges. Only Chain-building can weave a cooperating work force. Chain-building is deduction, if there is a single break, gap, disagreement in the chain, then there is no future for the project. A Team relies on consensus. Nothing happens till all agree -- like a well-functioning jury. Disagreement paralyzes. The aim of Chain-building is a workingTeam. As agreement develops, not only does the problem become sharply defined,but so also does its seemingly best solution. A Team emerges when members become united in the induction they are to undertake, in the experiment that will test the wild Pack hypothesis that was abducted, and in the Chain deductions which follow from it. The core sequence is Pack to Chain to Team. Each time a challenge is faced by a Team, its solution may succeed, encouraging the Team to continue cooperation. Or its solution may fail. In failure, there are two options: a) become defensive, circle the wagons, regress to a previous Chain in desperate hope of weathering the storm and regaining the Team mentality of "good old days". If this strategy fails, the Chain disintegrates destroying the Team, and the former members are forced to fend for themselves. b) become aggressive, send out scouts, progress to new Pack behavior in ambitious hope of constructing a better project, leading to a better Chain and thence a betterTeam. If this fails, members may fall back into a defensive Chain or disintegrate. Only a Pack can solve hard problems. Darwinian evolution and the human immune system are Pack processes. Only when problems can be made easy, because we have become better able to manage them, can Team-work succeed. In betweenTeams and Packs, there is the necessity of Chain building and maintenance, but also the danger of Chain breakage. Benjamin D. Wright Wright B.D. (1996) Pack to Chain to Team. Rasch Measurement Transactions 10:2 p. 501.
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# Teams, Packs and Chains, B Wright
In the 1920's Physicist Norman Campbell considered linear measurement of a social science variable to be impossible because he thought people could not be concatenated in any way similar to placing sticks end-to-end to measure length. More recently we have come to realize that people are always being "concatenated", i.e., accumulated to increase quantity according to specific rules. Teams, Packs and Chains are three methods of social concatenation.
Teams: Teams work as unions of perfect agreements. When Team members are given a task to perform, they must all agree on what to do (right or wrong). For a two-member team, helpful agreement (11) wins, but unhelpful agreement (00) loses. Disagreements (10) and (01) are absent because they are eliminated by the rules that define Team behavior. Let Team concatenation be indicated by x.
If Pni is the probability of success of person n on item i, and Pmi is the probability of success of person m on item i, then their Team odds of success, under Rasch model conditions, is: (Pnxm/(1-Pnxm)) = Pni*Pmi / (1-Pni)*(1-Pmi) = exp (Bn+Bm -(Di+Di)) Take logs and generalize to N Team members. Define N-member Team strength as BT. Then BT - Di = sum (Bn - Di)
The strengths of individual Team members relative to task difficulty (Bn - Di) add up to Team strength relative to task difficulty, (BT - Di). Teams are concatenations of relative strengths, accumulated in linear form. Adding a member more able than the task increases Team strength. Adding a member less able than the task decreases Team strength and weakens the Team. More is often not better, as has been frequently observed about committees.
Packs: Packs work as collections of helpful disagreements. When Pack members are given a task to perform, the first success wins for the Pack. If no member is successful, the Pack loses. Search- parties work this way. For a two- member Pack, helpful disagreements (10) and (01) win. Unhelpful agreement (00) loses. Helpful agreement (11) is absent because it is eliminated by the rules that define Pack behavior. Let Pack concatenation be indicated by +.
If Pni is the probability of success of person n on item i, and Pmi is the probability of success of person m on item i, then their Pack odds of success, under Rasch model conditions, is: Pn+m/(1-Pn+m) = ( Pni(1-Pmi) + (1-Pni)Pmi ) / (1-Pni)(1-Pmi) exp(Bn+m) = exp(Bn) + exp(Bm) a concatenation of absolute strengths accumulated in exponential form, which does not depend on Di. When Bn and Bm are similar, this is approximated by: exp(Bn+m) = 2 exp ((Bn + Bm)/2) Take logs and extend to N similarly able Pack members. Define N- member Pack strength as BP. Then BP = sum (Bn/N) + loge(N)
Pack composition is a collection because the helpful disagreements of Pack members collect to benefit the Pack. As N rises so must BP. The more the better. Unlike Teams, the strength of a Pack is independent of task difficulty.
Chains: Chain composition is a connection of commitments against harmful disagreement. Member actions are linked by mutual reliance on not disagreeing. An ability to maintain complete agreement is Chain strength. The harm that can result from a single disagreement is Chain weakness.
When the Chain members are given a task to perform, the first failure loses for the Chain. If there is no failing member, the Chain wins. For a two-member Chain, helpful agreement (11) wins. Lack of agreement (10) and (01) loses. Unhelpful agreement (00) is absent because it is eliminated by the rules that define Chain behavior. Let Chain concatenation be indicated by *.
If Pni is the probability of success of person n on item i, and Pmi is the probability of success of person m, then their Chain odds of success, under Rasch model conditions, is: Pn*m/(1-Pn*m) = Pni*Pmi /( Pni(1-Pmi) + (1-Pni)Pmi ) exp(-Bn*m) = exp(-Bn) + exp (-Bm) a concatenation of weaknesses accumulated in exponential form, which does not depend on Di. When Bn and Bm are similar this is approximated by: exp(Bn*m) = 0.5 * exp((Bn+Bm)/2) Take logs and extend to N similarly able Chain members. Define N-member Chain strength as BC. Then BC = sum (Bn/N) - loge(N)
Adding another member or link to a Chain always decreases Chain strength. Comparison: The Figure depicts the effectiveness of the three types of concatenation as group size (of equally able members) increases for a range of problem difficulties. Example: Imagine there are 10 people, all of ability -1 logit relative to the task to beperformed:Teamability=BT =10*-1=-10logitsPackability=BP =10*(-1/ 10) + loge(10) = 1.3 logits Chain ability = BC = 10 * (-1 / 10) - loge(10) = -3.3 logits so that: BP > BC > BT
Teams are most effective when a problem is very easy (at the top), otherwise Packs are most effective. Chains are least effective, except when a problem is very hard (at the bottom). Then Teams are least effective. A mob is a Team that chooses the wrong solution to a difficult social problem.
On a practical note, productive Japanese-style consensus- building, i.e., Team- work, requires that each difficult task be divided into several easy tasks, so that there is a high probability that each group member, acting alone, would have made the consensus-decision.
Teams, packs and chains. Wright BD. ... Rasch Measurement Transactions, 1995, 9:2 p.432