Freeze number 4 dated May 2023

# define freeze number
freeze_num = 4
# 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 4 dated May 2023#

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 8510 (45.1%) 10378
BIB 29664 28590 (96.4%) 1074
ELSA 18807 9080 (48.3%) 9727
EPICN 30445 15755 (51.7%) 14690
EXCEED 12008 11045 (92.0%) 963
FENLAND 12435 12072 (97.1%) 363
GENSCOT 25152 22391 (89.0%) 2761
GLAD 53824 52894 (98.3%) 930
MCS 40207 28003 (69.6%) 12204
NCDS58 18563 8913 (48.0%) 9650
NEXTSTEP 15629 6146 (39.3%) 9483
NICOLA 8739 5247 (60.0%) 3492
NIHRBIO_COPING 17183 17176 (100.0%) 7
NSHD46 5362 4289 (80.0%) 1073
SABRE 5251 4719 (89.9%) 532
TRACKC19 20630 19633 (95.2%) 997
TWINSUK 16902 16280 (96.3%) 622
UKHLS 42330 8851 (20.9%) 33479
Total 424163 285982 (67.4%) 138181

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 16741
(ii) Excluded because they died >=2020 963
(iii) Excluded because they withdrew from LPS 20401
(iv) Excluded because they dissented from UK LLC 1445
(v) Excluded because they dissented from record linkage 31408
(vi) Excluded because governance not established 18983
(vii) Excluded for other reasons 48240

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.

Contents