The Industrial Worker: Volume II The Industrial Worker: A Statistical Study of Human Relations in a Group of Manual Workers, Volume II [Reprint 2014 ed.] 9780674369238, 9780674369221

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THE INDUSTRIAL WORKER VOLUME II

THE INDUSTRIAL WORKER A STATISTICAL STUDY OF HUMAN RELATIONS IN A GROUP OF MANUAL WORKERS BY

T . N. W H I T E H E A D Associate Professor, Harvard Graduate School of Business Late Scientific Officer to the British

Administration

Admiralty

D R A W I N G S BY H E L E N M. M I T C H E L L Research Assistant, Harvard Graduate School of Business

Administration

VOLUME II

H A R V A R D U N I V E R S I T Y PRESS CAMBRIDGE, MASSACHUSETTS 1938

COPYRIGHT,

1938

BY THE PRESIDENT AND FELLOWS OF HARVARD COLLEGE

PRINTED AT T H E HARVARD UNIVERSITY PRESS CAMBRIDGE, MASS., U . S . A .

CONTENTS VOLUME

II

INTRODUCTION

I

The Use and Arrangement of the Figures

II

3

Note on Determination as a Measure of Correspondence between T w o Variables

III

4

Note on the Use of Compound Running Averages

FLGURES

REFERENCE NUMBER

AI A2 A3

6

. A.

CHAPTER

„ „ „ _ 1 H E G R O U P A N D T H E 1 EST R O O M

REFERENCE

Test Room Residents Plan of Test Room Bench Layout used by Operator 1 B.

WEEKLY

R A T E OF O U T P U T ,

2, 14, 18 2, 14 2

ITS R E P R E S E N T A T I O N , A N D ITS A N A L Y S I S I N T O T I M E

SPANS

B4

Weekly Rates of Output: Average N u m b e r of Relays Assembled per H o u r

B5 B6 B7 B8 B9 Bio Bu

4, 5, 6, 12, 15, 16 (sec. ι, 2, 3), 17, 18, 19, 21, 22, 26, 27 (sec. 2, Weekly Rates of Output: Running Averages of 52 Weeks 4, 21, 27 (sec. Weekly Rates of Output: Running Averages of 12 Weeks 4, 9, Weekly Rates of Output: Running Averages of 4 Weeks 4, T h e Isolation of Fluctuations within a Given T i m e Span 4, Fluctuations of W o r k i n g Speed: 12-52 Weeks' T i m e Span 4, 8, Fluctuations of W o r k i n g Speed: 4 - 1 2 Weeks' T i m e Span 4, 21, Fluctuations of W o r k i n g Speed: 1-4 Weeks' T i m e Span 4, 9, 10, C.

C12 C13 C14 C15 C16

CURVE

ANALYSIS

T h e Measurement of W a v e Length or T i m e Span T h e Independence of Fluctuations in Different T i m e Spans Comparison of Speed Fluctuations within a T i m e Span (Operators 3 and 4) Beginning and End of a State of Determination between T w o Variable Series T h e Independence of Determinations between T w o Variable Series in Various T i m e Spans (or W a v e Lengths) D.

D17 D18 D19 D20

FIGURES ILLUSTRATING W O R K

4) 4) 21 21 21 21 23 21

S T A T I S T I C A L L Y D E T E R M I N E D R E L A T I O N S H I P S IN T H R E E T I M E

21 21 21 21 21

SPANS

Pair Relationships (Determination) in 4 - 1 2 Weeks' T i m e Span 21, Pair Relationships (Determination) in 1 - 4 Weeks' T i m e Span 21, Pair Relationships (Determination) in 1 D a y - i W e e k T i m e Span Comparison between Relative Speeds and Relationships in 1 D a y - i W e e k T i m e Span for Pairs 2 and 4, 1 and 2, 3 and 4

23, 25 23, 25 21, 22 22, 23

VI

CONTENTS D.

S T A T I S T I C A L L Y D E T E R M I N E D R E L A T I O N S H I P S IN T H R E E T I M E

SPANS

(cont.)

REFERENCE

CHAPTER

NUMBER

D21

REFERENCE

D23

Total Pair Relationships in Three T i m e Spans: 4-12 Weeks, 1 - 4 Weeks, 1 D a y I Week Total Pair Relationships in Three T i m e Spans: Neighbor and Distant Pairs Shown Separately Pair Relationships on Certain Dates in 4 - 1 2 Weeks' and 1 - 4 Weeks' T i m e Spans

D24 D25 D26

Operator-to-Group Relationships in 1 D a y - i W e e k T i m e Span Operator-to-Group Relationships in 1 - 4 Weeks' T i m e Span Operator-to-Group Relationships in 4-12 Weeks' T i m e Span

D22

E.

E27 E28 E29 E30 E31 E32 E33

F35 F36 F37 F38 F39 F40

C H A N G E S IN R E L A T I O N S H I P ; T H E I R

A

CONNECTION

F O R M OF W O R K

MISCELLANEOUS

WITH OTHER

EVENTS

25 25 25 25 25 25 25

ELABORATION

26

INFORMATION

Group: Output, Output Rate, Quality of W o r k , Hours of Rest, Payment, Hours of W o r k , Rest Pauses, Hours of Unbroken W o r k 5, 6, 11, 16 (sec. 1) I.

143 144 145 146

WEEK

Frequency with W h i c h Daily (Actual) Output Ends in a N o u g h t or a Five H.

H42

23, 27 (sec. 8) 23, 25 23, 25 23

Dates of Changes: Pair Relationships in 4 - 1 2 Weeks' Span and Three Other Classes of Events Dates of Changes: Operator-to-Group Relationship in 4 - 1 2 Weeks' Span and Three Other Classes of Events Dates of Changes: Pair Relationship in 1 - 4 Weeks' Span and Three Other Classes of Events Dates of Changes: Operator-to-Group Relationship in 1 - 4 Weeks' Span and Three Other Classes of Events Changes in A l l Statistically Determined Relationships during Evendess Weeks . . . . A l l Events in Three Classes and Number of Eventful Weeks Unaccompanied by Changes in Relationship Percentage of Possible Changes in Relationship Coinciding with Six Stated Events . . G.

G41

ON V A R I O U S D A Y S OF THE

23

Comparison between W o r k i n g Rates on Tuesdays, Wednesdays, Thursdays, Fridays 8, 26 Comparison between W o r k i n g Rates on Mondays and Wednesdays . . . . 8, 26, 27 (sec. 4) Comparison between W o r k i n g Rates on Saturdays and Wednesdays 8, 26 Rates of Output for Each Monday 26 Rates of Output for Each Wednesday 26 Rates of Output for Each Saturday 26 Rates of Output for Days of the W e e k T a k e n Separately: Operator 4 only 26 F.

F34

COMPARISONS BETWEEN W O R K

23

H O U R S OF

REST

Hours of Rest during the N i g h t : Weekly Averages for Each Operator Hours of Rest during the N i g h t : Weekly Averages for a Small Control Group Average Hours of Rest by Days of the W e e k for Each Operator Average Hours of Rest by Days of the W e e k for a Small Control Group

6 6 6 6

vii

C O N T E N T S I.

H O U R S OF R E S T

(cont.)

REFERENCE

CHAPTER

NUMBER

147 148 149 150 151

REFERENCE

Hours of Rest by Days of the Week: Distribution Charts for Each Operator Weekly Hours of Rest vs. Concurrent Output Rate: Scatter Diagram for Each Operator Nightly Hours of Rest vs. Output Rate during Second Day Subsequently: Scatter Diagram for Each Operator Nightly Hours of Rest vs. Output Rate Next Day: Scatter Diagram for Each Operator Nightly Hours of Rest vs. Output Rate during Previous Day: Scatter Diagram for Each Operator J.

J52 J53 J54 J55 J56 J57 J58 J59 J60 J61 J62

ANNUAL

AND D A I L Y

K64 K65 K66 K67 K68 K69

L72 L73

6 6 6

HOLIDAYS

C H A N G E S OF R E L A Y

TYPE

Weekly Changes of Relay Type Experienced by Each Operator throughout Experiment Scatter Diagram: Output Rate vs. Weekly Changes of Relay Type: Operator 3, May 1927 to January 1930 Scatter Diagram: Output Rate vs. Weekly Changes of Relay Type: Operator 5, May 1927 to July 1929 Scatter Diagram: Output Rate vs. Weekly Changes of Relay Type: All Operators, Various Dates Scatter Diagram: Output Rate vs. Weekly Changes of Relay Type: Operators ι , 2, 3, 4, January 1932 to End Output Rates Every ¿-Hour: Operator 1 Alternately Assembling Relay Types R 1 3 1 6 and R 1 3 1 7 Output Rates Every ¿-Hour: Operator 2 Alternately Assembling Relay Types R 1 3 1 6 and R 1 3 1 7 L.

L70 L71

V A C A T I O N S AND

6

Seasonal Variations of Output Rate: Relay Test Group 8, 27 (sec. 3 ) Seasonal Variations of Output Rate: 5,500 Operators 8 Half-Hourly Variations of Output Rate 8 Effect of the Annual Vacation upon Output Rate: 15 Weeks Before and After 8 Effect of the Annual Vacation upon Output Rate: 15 Days Before and After 8 Effect of Christmas and N e w Year's Day upon Output Rate 8 Effect of Memorial Day upon Output Rate 8 Effect of Fourth of July upon Output Rate 8 Effect of Labor Day upon Output Rate 8 Effect of Thanksgiving Day upon Output Rate 8 Effect of Casual Holidays upon Output Rate 8 K.

K63

CYCLES:

6

T E M P E R A T U R E AND R E L A T I V E

9 9 9 9 9 9 9

HUMIDITY

Chicago Weather 1930: Wind, Sunshine, Precipitation, Temperature Chicago Weather — Daily Record 1927-1932: Mean Temperature, Relative Humidity at Noon Summer Weather: All Operators: Weekly Output Rate vs. Weekly Temperature and Weekly Relative Humidity Winter Weather: All Operators: Weekly Output Rate vs. Weekly Temperature and Weekly Relative Humidity

10 10 10 10

viii

CONTENTS L.

REFERENCE NUMBER

L74 L75 L76 L77 L78 L79 L80 L81

TEMPERATURE AND RELATIVE HUMIDITY ( c o n t . ) CHAPTER REFERENCE

Summer Weather: All Operators: Daily Output Rate vs. Combined Daily Temperature and Relative Humidity Winter Weather: All Operators: Daily Output Rate vs. Combined Daily Temperature and Relative Humidity Test Room Conditions 1927-1930: Temperature, Relative Humidity, Range of Temperature, Range of Relative Humidity Test Room Conditions, Summer: All Operators: Weekly Output Rate vs. Combined Weekly Temperature and Relative Humidity Test Room Conditions, Winter: All Operators: Weekly Output Rate vs. Combined Weekly Temperature and Relative Humidity Test Room Conditions, Summer: All Operators: Daily Output Rate vs. Combined Daily Temperature and Relative Humidity Test Room Conditions, Winter: All Operators: Daily Output Rate vs. Combined Daily Temperature and Relative Humidity Scatter Diagram: Operator 5, 1928, June 12-July 27: Daily Output Rate vs. Daily Mean Room Temperature

10 10 10 10 10 10 10 10

VOLUME II

INTRODUCTION I.

T H E U S E AND ARRANGEMENT OF THE FIGURES

Graphical presentation of numerical data may be used primarily as a method for recording numerical facts, though for this purpose it usually has no advantages over a tabular record. A second manner in w h i c h a graphical presentation may be used is to emphasize some one or two simple deductions from the data itself. This is its habitual use in published work, and it is one of the purposes of the figures in this volume. A third use of graphical presentation is as an instrument of analysis and deduction, for characteristics of numerical data, w h i c h are by no means obvious f r o m an inspection of the original tables, often become plain w h e n examined in graphical form. Many of the figures presented here have already done duty in this respect, and it is hoped that they may give the reader the same opportunity to exercise his independent judgment. Large parts of this book cannot usefully be read without a constant study of these figures, and it has seemed preferable to bind them separately so that the letterpress can be read with this second volume by the reader's side open at the relevant figure.

T h i s arrangement is familiar to the historian, w h o uses an atlas to supple-

ment his reading, but it has its disadvantages; these seem to be less serious in this instance than the more usual plan of binding figures in with the letterpress. So far as possible, the order of the figures has been arranged to keep together those that are most often referred to in connection with one another. T h e

figures

are numbered consecutively from ι to 81 in the order in w h i c h they are bound and, in addition, each figure carries a group letter, e.g. K - 6 6 . T h e number alone is sufficient as a reference, but each letter groups together all figures relating to one subject. Thus, all the figures bearing the letter Κ relate to Changes of Relay and all figures bearing the letter L relate to Temperature

and Relative

Type,

Humidity.

T h e subject of each letter and the titles of the particular figures are given in the Table of Contents at the beginning of this volume. O n the page facing each figure, will be found its title and a short statement giving certain supplementary information and, in case of doubt, stating h o w the numerical data for the figure have been obtained or calculated. There is no necessity to read these statements unless the reader wishes to do so. A l l the important references to figures in the main text contain a sufficient explanation to make their purpose clear; the effect of reading the accompanying statement every time a figure is referred to w o u l d probably be to confuse the argument with a mass of irrelevant matter. T h e statements accompanying the figures have two distinct purposes. First, any-

THE INDUSTRIAL WORKER

4

one who has read this book and may subsequently wish to refer to a particular figure can refresh his memory with respect to it without having to look up the relevant chapter every time. Moreover, if more information is needed, the statement indicates the chapter in which the principal reference occurs.

Secondly,

readers w h o are not content to take a figure at its face value but wish to understand the data or calculations on which it is based are given some opportunity of doing so. Most of the figures in this volume relate to the number of relays assembled in some given time. It is explained at the beginning of Chapter 4 that the operators assembled many different types of relays of varying degrees of complexity, and that for purposes of comparison the number of relays assembled is always given as the number of 'standard' relays (type E 9 0 1 ) which would have been assembled, assuming equal skill and application. So, in the following figures, all representations of work accomplished refer to the equivalent number of standard relays rather than to the actual number of relays assembled. There are no exceptions to this procedure unless stated in the letterpress accompanying a

figure.

T h e following notes presuppose a familiarity with the main text and with the figures in this book; they are intended for those interested in statistical or graphical technique. II.

N O T E ON DETERMINATION AS A M E A S U R E OF CORRESPONDENCE B E T W E E N T w o VARIABLES

T h e usual measure of correspondence between two variables is the 'correlation,' denoted by the letter, r. In the present work and in all figures, correspondence between two variables is measured in terms of the square of the numerical value of the correlation, ±

( r ) 2 . See, for instance, the letterpress accompanying Figure D - 1 7 .

2

T h e measure, r , is referred to as a 'determination.' T h e reasons for using determination as the measure, together with a f e w of its characteristics, are given at the end of Chapter 1. In certain cases, scatter diagrams are shown which might lead to a measure of correspondence between two variables, but these have not been worked out, for instance, see Figure Κ - 6 6 . Wherever such a calculation would genuinely lead to increased knowledge or security, it has been performed, but in the instance just cited it is obvious at a glance that the connection between the two variables must at best be trivial within the limits shown. T o express this fact numerically would be ridiculous pedantry. In Figures D - 1 7

t0

D - 2 0 , and D - 2 4 to D - 2 6 , the numerical values of determina-

tions between pairs of variables are actually plotted on the basis of calculation. In this case it becomes important to k n o w what reliance can be placed upon the statistical significance of these numerical values. T h e probable errors of these values have

INTRODUCTION

5

been calculated, but these are not shown, for they are definitely misleading. So far as they go, these calculations indicate a high degree of statistical significance in every single instance. Thus, Figure D-17 shows pair relations in the 4-12 weeks' time span. Operators 1 and 2 are shown as determinating between April 5-July 12, 1930, to an extent of -f- 97%» and the P.E. works out at about ± 2 % · Operators 2 and 3 determinate between December 5, 1931-March 5, 1932, to an extent + 6 6 % , with a P.E. of ± 1 1 % · Operators 3 and 4 determinate between December 15, 1928-July 13, 1929, to an extent + 8 1 % , with a P.E. of ± 4 % . These figures are typical of the rest but they are all based on a false premise, namely, the presumed independence of the succeeding values by either variable. Inasmuch as these succeeding values are read off a 'smoothed' curve, they cannot possibly be reasonably independent, nor, of course, are they completely dependent. Hence the calculations of probable error quoted above are a necessary, but not a sufficient, condition for the statistical significance of the determinations plotted in these figures. The type of social relationship shown by these determinations is amongst the most interesting of those discovered in the Relay Test group and the validity of the evidence is of the first importance, but it cannot be established by the usual tests of internal consistency alone. The validity of these determinations depends on the degree to which they are substantiated by other evidence relating to the Relay group. In Figures D-17, D-18, D-25, D-26, changes in the degree of determination between the pairs of variables occurred at about the dates shown and these changes were usually abrupt. The method by which these facts were obtained is described in Chapter 21. In Chapter 25 it was found that these changes coincided with the dates of certain other events to an extent which could not be accounted for by chance. This indicates that the dates on which the determinations were found to change value have a definite significance. Again, it has been shown that the degrees of determination between these pairs of variables bear a fairly constant relationship to sentiments which the operators were observed to entertain at the time. In a number of ways, in Parts IV and V of the text, it has been seen that the statistically deduced relationships between the operators reflected their relationships as observed by entirely different techniques. That these facts all dovetail together and form a coherent account of the social process in the Test Room must be the final test of significance for those statistical findings which cannot be validated by tests of internal consistency. One other rough test may be mentioned of the statistical significance of facts illustrated in Figures D - 1 7 t 0 D-19, and D-24 to D-26, as well as derived figures. If the determinations obtained were seriously affected by the play of 'chance,' we should expect to find almost as many weak negative as weak positive determinations. In fact, weak negative determinations are conspicuous by their absence, and on the rare oc-

6

T H E INDUSTRIAL WORKER

casions when negative determinations are found they are accompanied by evidence of disruptive sentiments between the operators involved. III.

N O T E ON THE U S E OF COMPOUND RUNNING AVERAGES

A simple running average is a well known device for obtaining a smoothed curve to represent the trends of a numerical series of any kind. The following table shows a numerical series and its simple running average of 3. Series

Running Average of 3

2 1

2.0

3

2.0

2 4 3 7 8 6 9 5 7 4 2

3.O 3-0 4-7 6.0 · 7.0 7-7 6.7 7-0 5-3 4-3 3.0

3 ι

2.0

The first figure in the running average of 3 is obtained by taking the average 2 -j- ι -{- 3 value of the first three figures in the original series (

= 2.0). This aver-

age, 2.0, is recorded opposite the middle of the three original figures of which it is a mean. Similarly, the second figure in the running average of 3 is the average χ -f- 3 + 2 value of the 2nd to the 4th figures in the original series (

= 2.0) and is re-

corded opposite the middle of these three figures. The remainder of the running averages are calculated and recorded in a similar manner. If the series of the running averages be plotted it will be found that they represent a trend curve for the original series, following the main contours of the latter without being burdened by all of its minor irregularities. Consider the series shown in Graph A of Sketch 12. The abscissa represents time to some scale, whilst the ordinate is a measure of the values of some variable such as working rate. The working rate took different values at different times, as shown in the plot. Suppose it be desired to illustrate the more persistent variations of working rate in this graph, this might be done by drawing a freehand curve through the mass of the points, but such a curve would be unlikely to represent any useful function of the original series; it would be subject to the whims of the draftsman.

SKETCH

A. TIME

•

12

SERIES

•

·

·

•• .

Β.

RUN. AVERAGE OF 10

C.

RUN. AVERAGE OF 3

•

D.

·/·

RUN. AVERAGE OF

3X3

·· · ·

.

·

8

THE INDUSTRIAL WORKER

T w o running averages have been calculated for the series shown in Graph A , namely a running average of 10 in Graph Β and a running average of 3 in Graph C. The points plotted in Graphs Β and C are those of their respective running averages and in each case a continuous curve has been drawn through these points. T h e first thing to notice is that the running average of 10 gives a less 'flexible' type of trend curve than the running average of 3. The former curve is exhibiting only the longer trends of the original series whilst the running average of 3 shows, in addition, trends of shorter duration in time. Thus, by a suitable choice of the 'base' number for a running average, a trend curve of any desired degree of flexibility can be produced. T h e second thing to notice is that the plot of the running average of 3 does not sufficiently indicate a trend curve. In drawing the smoothed curve through these points, there was found to be considerable latitude for variations of judgment and in this respect the series of running averages of 3 suffers in a lesser degree from the defect of the original series (Graph A ) . Running averages with a short base are apt not to indicate a trend curve with sufficient precision when the original series is markedly scattered. T h e problem is to produce a series, derived from the original series, such that it will indicate for the latter a trend curve of given flexibility and with adequate guidance for the draftsman's pencil. This can be done by means of a compound running average. The table below illustrates the calculation of a compound running average having bases of 3 X 3. The first two columns of the table are a repetition of those given in the previous table, the third column is a running average of 3 of the second column; it stands in the same relation to the second column as the second does to the first. Running Average Series

2 I 3

2 4 3 7 8

6 9 5 7 4 2 3 ι

of 3

Running Average of 3 χ 3 of the Original Series

2.0 2.0 3-0 3-0 4-7 6.0 7.0 7-7 6.7 7.0 5-3 4-3 3-0 2.0

2-3 2.7 3-6 4.6 5-9 6.9 7-1 7-1 6.6 5-5 4.2 3-1

INTRODUCTION

9

In the third column, the first figure is the average of the first three figures in the second column (

2.0 + 2.0 + 3.0

= 2.3) and this average is recorded opposite

the middle figure of the three it represents, and so on for the remaining figures in the last column. T o refer once more to Sketch 12, Graph D shows a compound running average of 3 X 3 of the original series plotted in Graph A . In Graph D the dots represent the actual series of the compound running average; a smooth trend curve for the original series has been drawn through the dots in Graph D. T w o things are apparent. The compound running average of 3 X 3 does, as the simple running average of 3 does not, provide an adequate pencil guidance in drawing a trend curve. Secondly, the trend curve indicated by the compound average of 3 X 3 is nearly as flexible as that provided by the simple average of 3. Actually, the trend curve drawn in Graph C is less flexible than that in D . The trend curve in C was drawn before the compound running average had been calculated and so much was left to the imagination of the draftsman that inadvertently some of the small fluctuations indicated by the plot were ironed out. This illustrates the fact that where the pencil is not adequately guided in drawing a trend curve, not only is the curve unlikely to represent anything correctly (as a gross example, it might habitually lie below or above the 'mean' of the plot, however the 'mean' be calculated), but such a trend curve will have a very uncertain and probably fluctuating degree of flexibility from place to place along its length. If, from a given series, a simple running average of base χ be calculated, and then, from the same series, a compound running average of base χ χ χ be also calculated, it will be found that the compound running average of χ χ χ indicates a trend curve slightly (but not much) less flexible than the simple average of base x. This can easily be tested by choosing a series, and a value for x, such that the simple running average does adequately guide the pencil. For instance, in Sketch 12, a compound running average of 10 X 10 would yield a trend curve only slightly less flexible than that shown in B. A few characteristics of compound running averages are stated below without proof. They are all susceptible of easy proof or demonstration. ι.) A compound running average can be built up of any number of running averages, e.g., 3 X 3 X 3 , each column being the running average of the previous aolumn. 2.) The bases of a compound running average can be dissimilar, e.g. 3 X 7 . such a case, the order in which the bases are taken is immaterial.

In

3.) If the object of calculating a compound running average is merely to obtain the greatest degree of 'pencil guidance' in drawing a trend curve with a given degree of flexibility, this is best achieved by making all the bases equal. It is rarely necessary to have more than a double running average to achieve a satisfactory 'pencil guidance.'

IO

THE INDUSTRIAL WORKER

4.) As a rough rule, the flexibility of a double running average having equal bases of η is about the same as that of a simple running average with a base 6/5 n. Thus, a compound running average of 3 X 3 has a flexibility of a simple running average with a base of about 4, and a compound running average with bases 10 X 10 has a flexibility of a simple running average of about base 12. In determining the degree of flexibility required of a trend curve based on a simple running average, or its compound equivalent, the following rule is useful. A simple running average will damp down any variation in the original series which only maintains itself for an interval shorter than the base of the simple running average. Any variation in the original series which maintains itself for at least as long as the base of the running average will be fully reflected in the resulting trend curve. 5.) Again, as a rough rule, I have observed the 'pencil guidance' of a compound running average to be rather better than that of a simple running average with a base equal to the product of the bases of the compound running average. Thus, a compound running average, of some given series, of 3 X 3 would have a pencil guidance rather better than a simple running average of base 9. In Sketch 12 it can be seen that the pencil guidances provided in Graphs Β (base 10) and D (bases 3 and 3) are not very different, the latter being slightly superior in this respect. 6.) As another example consider a compound running average with bases 4, 5, and 9. The pencil guidance of this plot would be somewhat superior to a simple running average having a base of 4 X 5 X 9 = 180. The flexibility of this compound running average can be roughly estimated as follows. The flexibility of the double running average having bases of 4 and 5 is roughly equal to a simple running average of base 6 / 5 X 5 = 6. The flexibility of a double running average having bases of 6 and 9 is greater than a simple running average of base 9, but less than one of base 6/5 X 9 ( = 10.8). Hence the flexibility of the original compound running average with bases 4, 5, and 9 would be found to be about that of a simple running average having a base of 10. 7.) It is a well-known fact that, if a series has a cyclical variation which repeats itself at exactly the same interval, this repeating variation can be entirely eliminated from a trend curve by using a simple running average whose base is any multiple of the interval in which the variation occurs. Thus, if a trend curve is required of the daily output of an employee working six days a week, and if the trend must not show weekly variations due to an abnormal rate on (say) Mondays, then the base of the running average should be 6 or some multiple of 6. A complication arises if the employee sometimes works six days in the week, at other times five days, and occasionally only four days in the week. A compound running average having bases of 6, 5, and 4 will eliminate any cyclical variation whose interval of recurrence is equal to any one of the bases. The bases can be used in any order for purposes of the calculation.

A-1 TEST ROOM RESIDENTS This figure shows who were actually resident in the Relay Test Room and for what periods; see date scale at the bottom of the figure. Residence implies that the individual normally spent the entire working hours of each day in the Test Room. The residents are composed of two groups; bench workers called operators, and the supervisory and clerical staff called supernumeraries in this book. When a line representing a resident changes level, this indicates that one individual has left the Test Room and has been replaced by another. If the line ever returns to its previous level then the first individual has returned to his, or her, old job (e.g. Operator 5). A dotted line (e.g. assisting inspector) indicates that the individual was not always resident during the period, but came in and out as the work required. A zigzag line (e.g. typist) indicates that no one individual was permanently allocated to the job. Those relay assemblers who have plain numbers or numbers with suffix 'a' are referred to as 'experts' (Ops. 1, 2, 3, 4, 5, ia, 2a, 5a). These operators all had several years' experience of relay assembling before they came to the Test Room. Assemblers with 'x' or 'y' suffixes are referred to as 'novices' (Ops. ix, 2χ, 3X, 4x, 5x, 3y). The novices had little or no previous experience of relay assembling before entering the Test Room. Beneath the residents in the figure is a record of the periods during which the operators were interviewed for experimental reasons. These interviews are described in Part III. The interviewers were never residents and they interviewed the operators in another room. Contractions op. — operator, sub — temporary substitute. L — Layout operator. I — Resident Inspector. Sup — Supervisor. Trans. — Transferred to another shop or department. T . R. — T e s t Room.

A-1 TEST

ROOM

RESIDENTS

OP.I

Lo id off

0p2 sub.

RELAY ASSEMBLERS

Op. 3

Op. 4

Left Firm

Op. 5

Op 5

"UT sub. LAYOUT

Trans

OPERATOR

sub. L

RESIDENT INSPECTOR

several changes of personnel - details unknown - one Γ married

(woman)

ASSISTING INSPECTOR (when I. was

overrun)

e

Assembly in T. R.

Trans, to another dept

SUPERVISOR

ex- sup. temporarily

m Τ R.

Trans.

¥ Promoted to " Supervisor

ASSISTANT SUPERVISOR JUNIOR

Resumed

- e x - op. 5a

Promoted left Τ R.

CLERK

Jran*0 fromTR.

Laid Laid off

Miss G

CALCULATOR

off

Laid, off ' * - L o t d off Mr. C.

TYPIST

typists

change

almost

daily

^dictaphone MR.

calculating^,

D.

INTERVIEWS

OF

OPERATORS M l s s 0

INTERVIEWERS (not residenti

· "ορβΓαίοΓ

eQCh

Miss e o t h

one interview

— I W27

1

1 1928

1

1 1929

installed

observing Laid off

1

1 1930

1

°P-

1 1931

a

"boot

1

22

interviews

. W32

1

1 1933

A-2 PLAN OF RELAY T E S T ROOM This plan is not drawn to scale in all its details, but the dimensions of the room are as shown, and the fittings are approximately correct. The Test Room was partitioned off from the main relay assembly shop, and was under the general supervision of the shop foreman. T h e main thing to notice is that the operators and the supernumeraries each sat in a row, and the two rows faced each other across the floor of the room, thus emphasizing the social gap between the bench workers and the 'white-collar' group. As a matter of unwritten custom, the former usually used the door at the right top of the plan, whilst the supernumeraries used the door at the left bottom of the plan.

A-2

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SHOP • Partition does not reach to ceiling REC0RDIN6 APPARATUS

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Β-δ ISOLATION OF WORK SPEED FLUCTUATIONS I N T H E 12-52 WEEKS' TIME SPAN In diagram i, curves representing the running averages of 52 weeks and 12 weeks have been superimposed for Operator 4. These curves are shown separately in Figures B-5 and B-6. In diagram 2, the differences between these two curves are plotted. This third curve is necessarily substantially insensitive to those fluctuations of Op. 4's work rate graph whose individual durations lie above 52 weeks or below 12 weeks. Thus the curve in diagram 2 shows those fluctuations in the original graphs whose individual fluctuations have time spans (durations) of between 12 and 52 weeks. Figure Β-9 shows similar curves for the five operators. By a similar process, curves are obtained representing only those fluctuations of work speed graphs lying between 4-12 weeks (Figure B-io) and 1-4 weeks (Figure B-11). For further information see Chapter 4.

B-9 FLUCTUATIONS OF WORKING SPEED IN T H E 12-52 WEEKS' TIME SPAN This figure shows only those fluctuations, in the operators' weekly output rate graphs (Figure B-4), whose individual durations lie between 12 and 52 weeks. The curve for each operator in this figure represents the difference between the values of the 52-week and the 12-week trend curves for that operator (see Figures B-5 and B-6). See letterpress accompanying Figure B-8, and for further discussion see Chapter 4.

B-9

B-10 FLUCTUATIONS OF WORKING SPEED IN THE 4-12 WEEKS' TIME SPAN This figure shows only those fluctuations, in the operators' weekly output rate graphs (Figure B-4), whose individual durations lie between 4 and 12 weeks. The curve for each operator in this figure represents the difference between the values of the 12-week and the 4-week trend curves for that operator (see Figures B-6 and B-7). See letterpress accompanying Figure B-8, and for further discussion see Chapter 4.

B-11 F L U C T U A T I O N S O F W O R K I N G SPEED I N T H E 1-4 WEEKS' TIME SPAN This figure shows only those fluctuations, in the operators' weekly output rate graphs (Fig. B-4), whose individual durations lie between 1 and 4 weeks. The graph for each operator in this figure represents the difference between the values of the 4-week trend curve and the weekly output rate graph for that operator (see Figures B-7 and B-4). See letterpress accompanying Figure B-8, and for further discussion see Chapter 4.

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C-12 T H E MEASUREMENT OF W A V E L E N G T H OR TIME SPAN This figure is intended to be used in connection with a discussion near the beginning of Chapter 21 on the method of measuring individual wave length in irregular curves and the meaning which can be attributed to such measurements.

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C-13 T H E I N D E P E N D E N C E OF F L U C T U A T I O N S I N D I F F E R E N T T I M E SPANS This figure is intended to be used in connection with a discussion in the middle of Chapter 21 on the independence of fluctuations in different time spans, all referring to the same original graph. The degree to which the actual techniques employed modify this independence is also referred to.

E Work Rate Curve

C-14 COMPARISON OF SPEED F L U C T U A T I O N S W I T H I N A T I M E S P A N (Ops. 3 and 4) Figure B - 1 1 shows those fluctuations of the operators' weekly rates of work whose individual durations lie between 1 and 4 weeks. The third and fourth graphs in B - 1 1 refer to Operators 3 and 4 respectively. To what degree do the fluctuations for these two operators correspond ? The top diagram answers this question for the period from December 29,1928, to July 13, 1929. Each dot is so placed as to indicate on the horizontal scale the reading from Β 1 1 , for Operator 3, for some particular week; the same dot is so placed with respect to the vertical scale as to indicate the reading from B - 1 1 , for Operator 4, for the same wee\. Every week between the dates mentioned (both dates inclusive) is represented by one dot. The determination for this scatter diagram proves to be + 0.86. The bottom diagram refers to the same pair of operators but for different dates. Exactly the same procedure could be adopted in a different time span (e.g., the 4-12 weeks' span, Figure B - i o ) . In this case, each dot would refer to one week as before, and the deviations of the two operators' working speeds for any given week could be read off the two curves in B-io. By this method, the degree to which the work speed fluctuations of any pair of operators determinate can be found in any time span and for any period of time. These periods of time were not arbitrarily chosen; see explanation accompanying Figure C - 1 5 . For further information see Chapter ¡21.

C-14 Deviotion Relays per Hour

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