Freeze number 9 dated August 2024

# define freeze number
freeze_num = 9
# import packages
import pandas as pd, sys
from IPython.display import HTML, display, Markdown
# create instance of freeze class
fp = 'S:/UKLLC - UKLLC Databank/UKLLC Systems/programs/quarterly'
sys.path.insert(0, fp)
import freeze_helper as fh
frehelp = fh.FreezeHelper(freeze_num)

Freeze number 9 dated August 2024#

Due to the UK LLC pooled sample being dynamic and the denominator changing over time, the UK LLC establishes a ‘data freeze’ of the pooled sample each quarter. Approved users are provisioned data against a set freeze which fixes their denominator at the start of their project and this remains fixed throughout the course of the project.

Table 1: Participants enrolled in LPS and included in the UK LLC resource#

Variation in contribution rates between LPS is mostly due to differences in fair processing. UK LLC continues to work with LPS to establish the governance permissions necessary to maximise the number of enrolled participants in the UK LLC resource.

display(frehelp.style_table(frehelp.get_table('table1')))
LPS N participants enrolled in LPS N (%) participants sent to UK LLC N participants not sent to UK LLC
ALSPAC 32144 6388 (19.9%) 25756
BCS70 18888 8538 (45.2%) 10350
BIB 29664 28590 (96.4%) 1074
ELSA 18807 9080 (48.3%) 9727
EPICN 30445 15755 (51.7%) 14690
EXCEED 12159 11142 (91.6%) 1017
FENLAND 12435 12071 (97.1%) 364
GENSCOT 25152 22391 (89.0%) 2761
GLAD 79309 78379 (98.8%) 930
MCS 40207 28009 (69.7%) 12198
NCDS58 18563 8972 (48.3%) 9591
NEXTSTEP 15629 7184 (46.0%) 8445
NICOLA 8739 5247 (60.0%) 3492
NIHRBIO_COPING 17183 17168 (99.9%) 15
NSHD46 5362 4289 (80.0%) 1073
SABRE 5251 4719 (89.9%) 532
TEDS 27890 10883 (39.0%) 17007
TRACKC19 20630 19633 (95.2%) 997
TWINSUK 17124 16486 (96.3%) 638
UKHLS 42330 8851 (20.9%) 33479
Total 477911 323775 (67.7%) 154136

Table 1 exclusions: The total number of participants not sent to UK LLC with reason for exclusion#

display(frehelp.style_table(frehelp.get_exclusions()))
Exclusion reason N participants
(i) Excluded because they died <2020 16650
(ii) Excluded because they died >=2020 1045
(iii) Excluded because they withdrew from LPS 24039
(iv) Excluded because they dissented from UK LLC 2651
(v) Excluded because they dissented from record linkage 30517
(vi) Excluded because governance not established 31160
(vii) Excluded for other reasons 48074

Footnotes with further details about exclusion criteria

(i) & (ii) UK LLC does not prohibit LPS from sending data for participants who have died. However, some LPS have policies which preclude these participants from inclusion in the resource. Data for participants who died on or after January 1, 2020 are particularly important for COVID-19 research, and so LPS were requested to send these data where possible.

(v) Participants who have dissented from linkage can still be included in the UK LLC resource, with permission flags set accordingly. However, some LPS policies preclude participants from inclusion.

Where a participant was excluded for more than one reason, LPS were asked to count participants once using the exclusion hierarchy (i-vii).

Information presented in Table1 was provided by the LPS at the latest quarterly File1 update corresponding with the freeze name printed at the top of this notebook.

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