An Investigation of an Automated Shelf. Reading and Inventory System for the. Clemson University Cooper Library

Transcription

1 An Investigation of an Automated Shelf Reading and Inventory System for the Clemson University Cooper Library Carissa Miller

2 Abstract An Investigation of an Automated Shelf Reading and Inventory System for the Clemson University Cooper Library The goal of this study was to determine whether an automated system could serve feasibly as an alternative to shelf reading at the Clemson University Cooper Library, while providing the additional benefits of performing a collection inventory. This goal was accomplished by performing a pilot study to compare the two approaches. The data suggests that an automated barcode system takes a statistically significant longer time to perform than manual shelf reading on a per book basis. However, the benefits of performing a collection inventory that an automated system provides warrant further expanded study of such systems efficiency. 2

3 Introduction The goal of this study is to determine whether an automated system could serve feasibly as an alternative to shelf reading at the Clemson University Cooper Library, while providing the additional benefits of performing a collection inventory. Background Shelf reading, a tedious manual task, is currently performed by having an employee visually scan the shelves to locate books out of order and to straighten shelves. Books slightly out of place are reshelved by the worker, while others are set aside to be reshelved later. This process, due to its monotonous nature, can only be done in short intervals of time in order to maintain a degree of accuracy in locating misplaced books. Even in short intervals, the chance of human error is high (especially in this case where minimum wage student labor is used). The Clemson University Library currently shelf reads the entire collection about three times a year. In some libraries, automated barcode systems are already being used as an alternative to shelf reading. Such systems work by having the worker scan the books on the shelves with a portable barcode reader. With this type of system, the high levels of mental fatigue that typically occur in manual shelf reading are not present. After scanning a range of books, the barcodes are then downloaded to a computer, where they are processed. This results in a list of book call numbers. If a book is not in sequence the book call number of the books on either side of the book in question are available so that a worker can find the book s location to correct the problem. The most common source of error is call numbers that are out of order. This is the same problem manual shelf reading seeks to identify. 1

4 The list generated by an automated system also identifies other types of problems such as books that are marked checked out but are actually on the shelves, books that are posted on a missing list but that are actually on the shelves, and books for which the barcode scanned is not in the circulation database. This information is extremely valuable. It provides an additional opportunity to locate missing books. The increased probability of locating missing books reduces patron and staff inconvenience and costs associated for interlibrary loans for books listed as missing. The information also allows the library to, in essence, do a physical book inventory, a task which the Clemson University Cooper Library currently does not do. A physical inventory allows for an accurate assessment of the library s holdings. Review of Literature A thorough review of literature revealed several categories of articles, which apply to this study. The first of these categories being current manual shelf reading practices. Shelf reading consists of a worker visually checking the shelves to locate misplaced books. A few libraries actually have workers slide books that have been shelf read to one side of the shelf so that they can easily continue if interrupted without losing their place (Anderson 4). Most libraries however do not require the books to be actually handled if they are in order. Some libraries have shelf readers remove misplaced books for later reshelving, but others have them reshelve the out of place book (Anderson 4). Manual shelf reading is a labor intensive, typically high burnout activity (Anderson 2); therefore, the time per day spent shelf reading is generally limited. Some libraries used two hours per day as a limit (Anderson 8), while others feel that one hour is a more optimal limit (Pederson 220). Clemson University library currently limits students to one hour of shelf 2

5 reading per day. Various studies have been done on shelf reading speed and accuracy, but many of these studies have been for short term special projects not the regular, day-to-day shelf reading activities that occur in many academic research libraries where most shelf reading is done by part-time student labor (Banks 40). Practicing circulation managers in academic libraries claim student assistants, assigned to shelf reading duties, often are poorly motivated to fulfill their work tasks (Banks 40). Banks examines motivation of the shelf readers as a factor in speed and accuracy in her 1990 study, the results of which showed that individual motivation made significant difference in shelf reading performance (Banks 45). Banks suggests that circulation supervisors collect data on employees individually and as a whole to determine a general average and possibly determine an optimum speed (45). Most libraries do collect and use shelf reading data in this manner. Pederson (219) calls shelf reading an onerous chore that is tedious and boring and very costly; however, he, like the other authors whose literature was reviewed, regard it as an essential to library collection maintenance. One reason for this is that some out of order books are virtually lost (Banks 39). Anderson notes that while shelf reading is costly and time consuming, not shelf reading costs the patrons access and cost the library time and money in conducting missing book searches, processing extra interlibrary loans, and purchasing duplicate copies, not to mention the additional time soothing disgruntled patrons (2). Anderson s justification of shelf reading is similar to the argument for justification of collection inventorying, which is another literature category of interest. Collection inventories have many of the same advantages and disadvantages of shelf reading. While shelf reading may provide for the location of missing books if they are severely (out of the appropriate section or 3

6 several ranges off) mishelved (Anderson 11), inventorying allows for the recognition of any book that is on the missing list. Chandel and Walia assert that every organization, big or small, has an administrative liability to know its stock position periodically (109). Historically the most common method used to inventory a collection is the shelf list (or shelf card list) method (Chandel and Walia 109). This involves using a shelf list (or drawer of shelf list cards) of the books and physically marking off each book on the list as one progresses through the collection (Webb 22). Due the high level of resources needed for inventory many view it as a phenomenon of diminishing return and a waste of man power (Chandel and Walia 108). For this reason many libraries conduct only partial inventories from which they make statistical projections based on random samples from the collection. Partial inventories negate the main advantage of collection inventories in that specific missing items for the entire collection are not identified (Freese 7). Many other libraries abandoned the practices of inventories all together (Freese 7). Many libraries have advanced from shelf cards to computerized databases of holdings and barcode systems for their circulation systems. There is a great deal of literature on this application of barcode systems. However, many libraries are just beginning to consider the application of barcode systems to collection inventories. Some articles address the current use of automated barcode systems for inventorying alone and for inventorying instead of shelf reading. It is difficult to inventory a collection, in which the material actually on the shelf changes from day to day and hour to hour (Emery 1). Automated systems allow the worker to simply scan the barcodes of the books on the shelf and let the computer system process the data. 4

7 Through the use of an external barcode the operation of scanning the books involves merely tilting a volume forward, scanning it, and replacing it (Emery 4). When barcode labels are consistently placed and easily accessible, 800 to 1,000 barcodes can be scanned in an hour (Webb 21). Also according to Webb, using the hand-held scanner requires little training and can be easily accomplished by a student or volunteer help resulting in a considerable savings of professional time (21). Once the data are downloaded from the portable scanner to the computer system, the system can produce a current inventory list while taking into account books that are checked out or currently reside elsewhere in the library (Webb 22). There are many things that can be revealed by the reports generated, such as items that are marked as withdrawn but actually on the shelves, items for which there is a patron hold, and items that have been reported as missing (Emery 7). Additionally these reports can show items that are not shelved in proper call number sequence and items that are shelved in the wrong library location (Emery 7). To locate the books shelved out of sequence, the system provides the call number of the book scanned immediately prior to and immediately after the out of sequence book (Allen 104). From the inventory report, trained shelvers can locate misplaced items and return them to their proper places (Webb 22). Webb also asserts that between normal inventories several libraries use this shelf reading functionality of the inventory system on its own (21). From the literature, a general list of some of the necessary characteristics of the barcode hardware was determined. The essential characteristics of the hardware are that it must be lightweight, sturdy, portable, easy to use, reliable, and data must be downloadable to a standard PC (Allatt, Fisher, and Yeadon 162). It must also be able to store a full day s worth of data, 5

8 approximately 9,000 barcodes (Webb 21). The battery life of the scanner is also important. Some additional features that are desirable but not essential, include: the equipment be industry standard, the scanners be detachable so that they can be transferred to IBM compatible PCs when not in use on portable units, and that a laser scanner is used rather than a light pen (Allatt, Fisher, and Yeadon 162). The logic behind the last characteristic is that the tip of a light pen (wand) tends to wear down and the barcode becomes warn from the contact between the two, whereas laser gun readers do not make contact with the barcode (Halliday 9). According to Allen, some libraries have investigated using radio frequency wireless telecommunication to transmit data to the computers interactively (102). However, at the time Allen s article was published (1995), this technology was disregarded due to high cost and lack of industry standards (102). 6

9 Method Location Selection To determine differences in labor requirements between automated barcode scanning and manual shelf reading, a pilot study was performed. This study compared the labor requirements with respect to time and accuracy using the two methods. The location of the study was selected by contacting software vendors to discover which local libraries used automated barcode systems. After several libraries were identified these libraries were contacted to determine the specifics of their systems. There were two things essential to the library being a candidate for the study. The first of these was that it used an automated barcode system that had on-shelf inventory capabilities. Secondly, the library had to place its barcodes in a standard position on the outside of the book. Many libraries met the first criteria but not the second. After a library was identified that met the above criteria and was willing to participate, all that remained was scheduling the study. This proved to be very difficult due to the libraries time constraints and other scheduling difficulties. For this reason the initial library identified was unable to participate and another library had to be selected. This put tremendous constraints on the design of the experiment. Design of Experiment Two designs for the experiment were developed. The initial design was based on better conditions than the second was. The second design was a modification of the first design due to various constraints. Under ideal circumstances, two ranges of approximately 400 books would be used. Each range would be checked twice using an automated barcode system to ensure 7

10 books were in the correct order. Then 10% of the books would be strategically misplaced. To determine which books were misplaced, a random number table was used to generate a list of numbers that fell in the ranges. The participants would then use an automated barcode scanner to check range one and then manually shelf read range two. A week later the ranges would be reset up identically to the previous set up and then the participants would use the barcode scanner on range two and manually shelf read range one. The reason for the delay between the two periods of data collection was to minimize the effect of participant memorization of misplaced books during barcode scanning being used during shelf reading. The ideal study was designed to incorporate four participants. Two of these participants would be librarians at the facility being used, who were familiar with both the automated barcode system and with manual shelf reading. The other two participants would be students who were experienced manual shelf readers only. Ideally more participants would have been used, but there were labor constraints on the part of the librarians and student participants. The data collected would include data on the accuracy and speed of each participant on each range. Each participant s time would be recorded after they finished scanning a range with the barcode reader or manually shelf reading a range. After each participant had used the barcode scanner the data it collected would be transferred to the computer where a list of out of order books and missing books could then be generated. This would be used to determine the accuracy of the participants while using the barcode scanner. To determine the accuracy of the participants while manual shelf reading, the participants would be required to place a post-it- 8

11 note on all books they found out of order. After the participants finished manually shelf reading a range, the number of misplaced books correctly identified was recorded. The actually conducted study was designed under severe time constraints, so the sizes of the ranges were reduced to approximately 200 books. Additionally modifications were made to the make up of the participants. Four inexperienced shelf readers were used for the study instead of a mix of experienced librarians and students. This was due to scheduling difficulties and unavailability of experienced students. Data Collection Two 2 2 factorial designs were used to analyze data, one for speed data and one for accuracy data. The two factors were the method (automated barcode method and manual shelf reading) and the range (range one and range two). Four replicates were used. The data collected can be seen in Table 1. The tasks are listed in the order the subject performed them. In regards to accuracy, several aspects were examined. The first thing examined was the number of out of order books the subject had identified. All failures to identify out of order books were recorded as errors. Unexpectedly, some subjects identified properly sequenced books as out of order. This occurrence was reported as false error. All errors were recorded separately by type. These two types of errors, failure to identify errors and false errors, applied to manual shelf reading. With respect to scanning, the errors were of a different type since scanning did not require the subject to actually mentally determine which books were out of order. The first error that applied to scanning was an inventorying error, where the subject must have skipped scanning a book that was out of order. In manual shelf reading it is impossible to determine 9

12 whether a missed out of order book was simply skipped or incorrectly mentally processed as being in order. However, missing an out of order book while shelf reading (failure to identify error) has the same result as missing an out of order book while barcode scanning (inventorying error); therefore, the two errors were treated analogously for the purposes of data analysis. The second type of error applying to scanning was also unexpected. This type of error, which will be termed a sequencing error, involves the subject scanning a book out of sequence. In this instance the subject skipped a book; however, the individual realized their error and rectified it by scanning the book after scanning later books. This registered the initially skipped book out of order in the system; hence, generating a false error. In manual shelf reading, if a book was skipped and returned to, then an error would not occur. For this reason this occurrence in scanning was recorded as a separate type of error. Since either method of generating a false error, via barcode scanning or manual shelf reading, results in an external action to verify the error, these two types of errors, false errors and sequencing errors, will also be treated analogously. 10

13 Results Data was recorded for each subject on the task performed (method used and range used), the order the tasks were performed in, the time to complete each task, the number of correctly identified out of order books, and the number and type of any errors made. Then, the time per book was calculated based on the number of books in the range the task was performed on. These results can be seen in Table 1. Table 1-1: Data Table Subject Order Task Performed Method Range Time (minutes) Time (min/book) # of correct out of order books found Errors 1 1 SR BC B 3 SR D 4 BC SR D 2 BC C 3 SR BC BC SR A 3 BC C 4 SR D 4 1 BC B 2 SR A 3 BC SR D Type Table 1-2: Ranges Defined Table 1-3: Errors Defined Ranges # of # of Error Description Books Errors types A False Error B Inventorying Error C Sequencing Error D Failure to Identify Error 11

14 As can be seen in Figure 1, a learning curve can be seen in that the subjects time per book decreases for barcode scanning for three of the four subjects between the first range of books scanned and the second. For shelf reading half of the subjects time per book decreased between the first and the second ranges shelf read. However, the other half of the subjects time per book increased. This can be seen in Figure 2. It is interesting to note that both subjects whose time per book increased completed the tasks in the same order and ended with shelf reading. Figure 1: Barcode Scanning Time Per Book Barcode Scanning 0.16 Time (min/book) First Scanning Second Scanning Subject 1 Subject 2 Subject 3 Subject 4 *(R1, R2) denotes the order the ranges were processed, ex: range 1 processed first, range 2 processed second Figure 2: Shelf Reading Time Per Book 12

15 Shelf Reading Time (min/book) First Reading Second Reading Subject 1 Subject 2 Subject 3 Subject 4 13

16 Overall accuracy is the total number of errors each subject made on each task. The graph of all of the subjects overall accuracy (Figure 3) of task performance in the order the tasks were completed, shows no consistent trend of accuracy increase or decrease over time. Figure 3: Overall Accuracy Over Time Accuracy Over Time Accuracy (# of errors) Order Task Performed Subject 1 (SR2,BC2,SR1,BC1) Subject 2 (BC1,SR1,BC2,SR2) Subject 3 (SR2,BC2,SR1,BC1) Subject 4 (BC1,SR1,BC2,SR2) *Order of tasks performed, method and range, listed for each subject With respect to barcode scanning accuracy, as shown in Figure 4, three out of four subjects also exhibited a learning curve in this aspect of barcode scanning, as their number of errors decreased from one to none. With respect to shelf reading accuracy as shown in Figure 5, there is nothing to suggest a learning curve, as only one subject decreased in number of errors made between the first and the second ranges shelf read. 14

17 Figure 4: Barcode Scanning - Accuracy Barcode Scanning 1.2 Accuracy (# of errors) Subject 1 Subject 2 Subject 3 Subject 4 0 First Scanning Second Scanning Figure 5: Shelf Reading - Accuracy Shelf Reading 2.5 Accuracy (# of errors) Subject 1 Subject 2 Subject 3 Subject 4 0 First Reading Second Reading 15

18 In addition accuracy was examined in terms of false/sequencing errors and failure to identify/inventorying errors in both manual shelf reading and barcode scanning. It is interesting to note that although two types of errors could be made on a task, no subject made more than one type of error on a task. As shown below in Figures 6 and 7, respectively, no trend can be determined with regard to the number of false/sequencing errors of the subjects while shelf reading or with regard to the number of and failure to identify/inventorying errors while barcode scanning. Figure 6: Barcode Scanning Failure to Identify/Inventorying Errors Barcode Scanning Accuracy (# of Failure to Id/Inventorying errors) First Scanning Second Scanning Subject 1 Subject 2 Subject 3 Subject 4 Figure 7: Shelf Reading False/Sequencing Errors 16

19 Shelf Reading Accuracy (# of False/Sequencing errors) First Reading Second Reading Subject 1 Subject 2 Subject 3 Subject 4 The number of false/sequencing errors for barcode scanning for each subject remained at zero for two of the subjects and decreased to zero on the second scan for the other two subjects as shown in Figure 8. Figure 9 shows that this is also the trend for the number of failure to identify/inventorying errors with regards to shelf reading. Figure 8: Barcode Scanning False/Sequencing Errors Barcode Scanning 1.2 Accuracy (# of False/Sequencing errors) Subject 1 Subject 2 Subject 3 Subject 4 First Scanning Second Scanning 17

20 Figure 9: Shelf Reading Failure to Identify/Inventorying Errors Shelf Reading Accuracy (# of Failure to Id/Inventorying errors) First Reading Second Reading Subject 1 Subject 2 Subject 3 Subject 4 After examining the possible effects of learning curves, the data was examined to determine the correlation between time per book and accuracy. This was done by plotting the accuracy of each subject on each task against the time per book recorded for that task for that subject. Barcode scanning and shelf reading and were compared separately, and the results can be seen in Figures 10 and 11, respectively. Neither method showed a consistent correlation between time per book and accuracy. Figure 10: Accuracy vs Time in Barcode Scanning Accuracy vs Time in Barcode Scanning 1.2 Accuracy (# of errors) Time (min/book) Subject 1 (BC2,BC1) Subject 2 (BC1,BC2) Subject 3 (BC2,BC1) Subject 4 (BC1,BC2) 18

21 Figure 11: Accuracy vs Time in Manual Shelf Reading Accuracy vs Time in Manual Shelf Reading Accuracy (# of errors) Time (min/book) Subject 1 (SR2,SR1) Subject 2 (SR1,SR2) Subject 3 (SR2,SR1) Subject 4 (SR1,SR2) 19

22 After looking at the correlation between time per book and accuracy, the data was analyzed using the 2 2 factorial design discussed previously. The two factors were the method (automated barcode method and manual shelf reading) and the range (range one and range two). Four replicates were used. Both the time per book data and overall accuracy data were analyzed in this fashion, and analysis of variance tables were constructed using an alpha of.05 (resulting p values are also listed). In Table 2, the ANOVA based on time per book data, it appears that the time per book for the two methods is statistically significantly different (resulting p value is ). Barcode scanning takes on average.03 minutes per book longer. In Table 3, the ANOVA based on accuracy data, no statistically significant differences can be determined. Table 2-1: Time Per Book - Summary Statistics Anova: Two-Factor With Replication - Time SUMMARY BC SR Total Range 1 Count Sum Average Variance Range 2 Count Sum Average Variance E Total Count 8 8 Sum Average Variance Table 2-1: Time Per Book ANOVA ANOVA Time (min/book) Source of Variation SS df MS F P-value F crit 20

23 Range Method Interaction E E Within Total Figure 3-1: Accuracy - Summary Statistics Anova: Two-Factor With Replication - Time SUMMARY BC SR Total Range 1 Count Sum Average Variance Range 2 Count Sum Average Variance Total Count 8 8 Sum 4 9 Average Variance Figure 3-2: Accuracy ANOVA ANOVA Accuracy Source of Variation SS df MS F P-value F crit Range Method Interaction Within Total

24 Conclusions Due to the constraints of time and labor for this study, the amount of data collected is not sufficient to generate any conclusive findings. However, some trends were observed that warrant further study. There is some evidence of learning curves being factors in barcode scanning speed and shelf reading accuracy. Since all subjects were inexperienced with both shelf reading and barcode scanning, further testing over a longer period of time could show the presence of a learning curve with respect to time and accuracy of both shelf reading and barcode scanning. Such further testing could also show that initial suggestions of a learning curve could just be fluctuations in the data. From this study there appears to be no correlation between accuracy and time per book. This is counterintuitive. Therefore, this correlation or lack thereof could also warrant further study, as the effect of learning curves could have rendered the data collected as just an initial bias. The analysis of the time per book data using the 2 2 factorial design discussed previously suggested that there is a significant difference in the time per book between the two methods. While barcode scanning provides the benefits of manual shelf reading along with the benefits of collection inventory, barcode scanning takes on average.03 minutes longer per book. This per book difference suggests that barcode scanning may not be a feasible alternative to shelf reading. However, when taking into account the benefits of performing inventory that are gained through barcode scanning, this time difference between the two methods may become a 22

25 less important factor in the evaluation of a system using barcode scanning as an automated shelf reading and inventory system for the Clemson University Cooper Library. Inclusion of the benefits of inventory warrants the further exploration of the efficiency of automated barcode systems. One reason for this is that the Clemson University Cooper Library is currently looking for new circulation software. Several software packages include modules for automated barcode systems that can be used for inventory purposes and as alternatives to shelf reading. If further investigation shows automated barcode systems as favorable to the current manual shelf reading practices, then a module that supports inventory and shelf reading could be a criterion in software selection. 23

26 References Allatt, Paul. Fisher, Mark. and Yeadon, Janice. Automated Stocktaking at Imperial College. Program. (Vol. 31(2) April 1997): Allen, Virginia. Automated Library Inventory Using Barcodes. International Association of Aquatic and Marine Science Libraries and Information Centers Conference Series. (Conference 23 rd 1997): Anderson, Dawn R. Method Without Madness: Shelf-Reading Methods and Project Management. College and Undergraduate Libraries. (Vol. 5(1) 1998): Banks, Julie. Shelf Reading: A Pilot Study. Collection Management. (Vol. 13 (1/2) 1990): Chandel, A. S. and Walia, R. K. Computer-Assisted Stock-Verification System. Libri. (Vol. 43(2) 1993): Emery, Charles D. The use of Portable Barcode Scanners in Collections Inventory. Collection Management. (Vol. 13(4) 1990):1-17. Freese, Melanie. Missing Links: Smart Barcodes and Inventory Analysis at Hofstra University s Axinn Library. Library and Archival Security. (Vol. 9(1) 1989):3-17. Halliday, Caroline. Reading Between the Lines. PC Magazine. (Vol. 7 (12) June 28, 1988): Pederson, Wayne A. Statistical Measures for Shelf Reading in an Academic Health Sciences Center Library. Bulletin of the Medical Library Association. (Vol. 77 April 1989): Webb, Donna R. Sidebar 3: Inventory. Library Hi Tech. (Vol. 12(1) 1994):