2018 CUL Monograph Accounted For Study: Findings
02 November 2018 14:28
Investigators
- Adam Chandler, study design, data analysis
- Wendy Wilcox, study design, project management and data collection
- Joanne Leary, study design, data collection
Acknowledgements
- Jenn Colt, Google App installation
- Sara Amato (EAST consortium data analyst), assisted with sampling method, software installation, and data sharing
2017 CUL Tattle-tape task force recommendations
To: Xin Li
From: Adam Chandler (chair), Susie Cobb, Maureen Morris, Wendy Wilcox
Date: December 19, 2017
Subject: Tattle-tape Task Force Final Report
Even though members of our task force are not confident that it is actually preventing theft we must recommend continuing tattle-taping because staff, primarily selectors, clearly oppose changing the policy at this time. Feedback from access services staff was split: smaller units felt that tattle-taping was effective at preventing theft while larger units felt that tattle-taping was ineffective in protecting open stack collections. These responses make sense given the different approaches to responding to gate alarms. Before the CUL tattle-taping policy is changed, we recommend these steps:
- Replacement fees should by recycled back into supporting replacement of missing and lost materials.
- Centralize and streamline the decision-making process and funding for replacing missing and lost materials.
- Consider conducting an inventory of the library’s open stacks collections using the methodology (and tools, perhaps) employed in the EAST validation study to use as a baseline to inform present and future decision making on this issue.
What is the EAST validation study?
“In order to evaluate the statistical likelihood that a retained volume exists on the shelves of any of the institutions, the EAST incorporated sample-based validation studies. The specific goals of this study were to establish and document the degree of confidence, and the possibility of error, in any EAST committed title being available for circulation. Results of the validation sample studies help predict the likelihood that titles selected for retention actually exist and can be located in the collection of a Retention Partner, and are in useable condition.” [https://eastlibraries.org/validation]
EAST Results
Overall, EAST can report a 97% availability rate.
The aggregated results from both cohorts (312,000 holdings across the 52 libraries) showed:
* 97% of monographs in the sample were accounted for: mean: 97%, median: 97.1%, high of 99.8% and low of 91%. (Note: “accounted for” includes those items previously determined to be in circulation based on an automated check of the libraries’ ILS.) * 2.3% of titles were in circulation at the time of the study
* 90% of the titles were deemed to be in average or excellent condition with 10% marked as in poor condition. Not surprisingly, older titles were in poorer condition.
A few notable observations include:
* Items published pre-1900 were in significantly poorer condition; some 45% of these items ranked “poor” on the condition scale
* An item being in poor condition was also somewhat correlated to its subject area
* The most significant factor for an item being missing was the holding library.
Cornell baseline study data collection
Study conducted between April and July. We sampled 6006 monograph across campus. Wendy Wilcox led the team that did the data collection in the stacks. Some notes: Annex was excluded because the stacks there are closed; Fine Arts was excluded because they are in the middle of a building transition. Loaction codes in HLM were merged into one group. Some items were removed because they did not actually fit the criteria of our study, leaving 5952 items in our dataset.
AF (accounted for) = checkedout + present
What variables are in the dataset?
glimpse(df)## Observations: 5,952
## Variables: 36
## $ barcode <chr> "31924062968908", "31924072130184...
## $ present_or_not <fct> Present, Present, Present, Presen...
## $ location_code <chr> "afr", "afr", "afr", "afr", "afr"...
## $ norm_cn <chr> "DT 32 R 61", "DT 3...
## $ call_nbr_display <chr> "DT32 .R61", "DT328.M53 .H3613x 1...
## $ call_nbr_norm_item <dbl> NA, NA, NA, NA, NA, NA, NA, NA, N...
## $ enumeration <chr> NA, NA, NA, NA, NA, NA, NA, "c.2"...
## $ item_control_nbr <chr> "3723592", "4103508", "7620171", ...
## $ title <chr> "Death of Africa. By Peter Ritner...
## $ bib_rec_nbr <chr> "1968678", "2249095", "5689943", ...
## $ historical_charges <dbl> 1, 0, 2, 0, 0, 10, 2, 0, 56, 1, 2...
## $ catalog_url <chr> "https://newcatalog.library.corne...
## $ worldcat_oclc_nbr <chr> "412793", "59941146", "148569", "...
## $ row_number <dbl> 1585081, 735421, 2715241, 850681,...
## $ us_holdings <dbl> NA, NA, NA, NA, NA, NA, NA, NA, N...
## $ condition <fct> Acceptable, Excellent, Acceptable...
## $ initials <chr> "mah94", "mah94", "mah94", "mah94...
## $ barcode_validation <chr> "yes", "yes", "yes", "yes", "yes"...
## $ status <dbl> NA, NA, NA, NA, NA, NA, NA, NA, N...
## $ timestamp <dttm> 2018-07-06 13:56:23, 2018-07-06 ...
## $ id <dbl> 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11...
## $ item_status_desc <chr> "Not Charged", "Not Charged", "No...
## $ item_type_name <fct> book, book, book, book, book, boo...
## $ length_cn <dbl> 9, 22, 14, 19, 22, 20, 18, 11, 12...
## $ begin_pub_date <dbl> 1960, 1993, 1971, 2013, 2010, 197...
## $ x300_field <chr> "312 p. 22 cm.", "xv 199 p. : ill...
## $ number_pages <dbl> 312, 199, 372, 257, 216, 310, 301...
## $ historical_voyager_circs <dbl> 0, 0, 2, 0, 0, 2, 1, 0, 9, 1, 1, ...
## $ loan_interval <chr> NA, NA, "D", NA, NA, "D", "D", NA...
## $ any_reserve_circs_0_no_1_yes <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...
## $ is_missing <fct> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...
## $ is_accountedfor <fct> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ...
## $ location_group <fct> afr, afr, afr, afr, afr, afr, afr...
## $ has_circulated <dbl> 0, 0, 1, 0, 0, 1, 1, 0, 1, 1, 1, ...
## $ is_oversize <dbl> 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...
## $ age <dbl> 58, 25, 47, 5, 8, 47, 24, 53, 28,...Bootstrap simulation to estimate standard error
Cornell’s aggregate accounted for rate is 96.4% and we are 95% confident that the true proportion of accounted for monographs across CUL is between 0.959, 0.969.
Are there differences across CUL units in the percentage of monographs accounted for? Yes.
## # A tibble: 9 x 5
## location_group mean se total num_missing
## <fct> <dbl> <dbl> <int> <dbl>
## 1 mus 0.990 0.00994 102 1
## 2 afr 0.979 0.0214 49 1
## 3 olin 0.974 0.00277 3221 84
## 4 asia 0.961 0.00525 1282 50
## 5 law 0.950 0.0106 400 20
## 6 math 0.949 0.0204 116 6
## 7 uris 0.948 0.0132 270 14
## 8 mann 0.928 0.0158 280 20
## 9 hlm 0.924 0.0181 210 16
How does Cornell compare to the EAST consortium libraries?
Tattle-tape: What evidence do we have that security stripping improves AF rates? In other words, what is our estimate of the effect size (i.e., return on investment) for libraries that operate security systems?
Exhibit A: Cornell
At Cornell, we had an experiment ready to be conducted because there is one unit that does not use security stripping or gates, Law. Our intuition might tell us that the Law AF rate should therefore be lower than the other units. That is not the case. The Law mean AF (accounted for rate) in this sample is right in the middle of pack, with confidence intervals overlapping other units that have both higher and lower AF rates.
Exhibit B: EAST surveyed libraries that participated in their validation study about security practices
Sometime after completing it’s validation study, EAST conducted a survey of participating libraries to find out about the theft deterrence practices. 32 libraries responded. The library names are anonymized.
| library | tattletape_yes_no | validation_score |
|---|---|---|
| anteater | Yes | 0.984 |
| armadillo | No | 0.948 |
| axolotl | No | 0.984 |
| buffalo | Yes | 0.935 |
| camel | Yes | 0.976 |
| chameleon | Yes | 0.951 |
| cheetah | No | 0.990 |
| chipmunk | Yes | 0.953 |
| chupacabra | No | 0.973 |
| crow | Yes | 0.975 |
| dolphin | Yes | 0.989 |
| giraffe | Yes | 0.994 |
| grizzly | Yes | 0.990 |
| hedgehog | No | 0.953 |
| hippo | Yes | 0.963 |
| ifrit | Yes | 0.978 |
| iguana | No | 0.956 |
| jackal | Yes | 0.997 |
| koala | No | 0.983 |
| lemur | Yes | 0.916 |
| leopard | Yes | 0.992 |
| liger | Yes | 0.988 |
| llama | Yes | 0.982 |
| manatee | No | 0.984 |
| monkey | Yes | 0.953 |
| narwhal | No | 0.970 |
| nyan cat | Yes | 0.994 |
| otter | Yes | 0.990 |
| panda | Yes | 0.968 |
| quagga | No | 0.982 |
| squirrel | Yes | 0.995 |
| wombat | Yes | 0.967 |
## # A tibble: 2 x 2
## tattletape_yes_no mean
## <fct> <dbl>
## 1 No 0.972
## 2 Yes 0.974## # A tibble: 2 x 5
## af se total status n
## <dbl> <dbl> <int> <chr> <chr>
## 1 0.972 0.00476 1000 no 10
## 2 0.974 0.00455 1000 yes 22
In this experiment we divided the EAST libraries into two groups, the 22 libraries in the survey with security systems vs. the 10 libraries with no security systems, and generated accounted for (AF) rates and standard errors using bootstrap simulation for each group. The difference in AF rates can be explained by random noise, as we see from the overlapping 95% confidence intervals. We conclude again that the effect size of having a security system is zero.
Recommendations
- Where confidence intervals are widest, do more sampling in Cornell unit libraries to improve the accuracy of our estimates.
- Security stripping is only one variable that might account for differences in the percentage of items accounted for across different libraries, and from the empirical evidence we’ve gathered, it isn’t a variable with any predictive power here or across the EAST consortium. Therefore, we believe that a better investment is more support for open stacks control and management at units with lower accounted for rates.
- Create a statistical model that includes multiple variables to identify items with higher probability of being unaccounted for in the open stacks. This work is already underway.