# Which longitudinal weights to use?

**URL:** <https://forum.ipums.org/t/which-longitudinal-weights-to-use/2641>\
**Category:** CPS\
**Created:** [October 29, 2018, 8:35pm UTC](https://forum.ipums.org/t/which-longitudinal-weights-to-use/2641 "2018-10-29T20:35:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![avilla4](https://avatars.discourse-cdn.com/v4/letter/a/c4cdca/32.png) [@avilla4](https://forum.ipums.org/u/avilla4)\
**Post date:** [October 29, 2018, 8:35pm UTC](https://forum.ipums.org/t/which-longitudinal-weights-to-use/2641/1 "2018-10-29T20:35:00Z")

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When we are linking individual-level data from two consecutive months of the CPS should we use the LNKFW1MWT or PANLWT weights? What is the difference between these two weights? The article by Drew, Flood and Warren (2014) on which the longitudinal weights are based (LNKFW1MWT) doesn’t provide clear guidelines. The online information on the IPUMS website also doesn’t give much information. Drew, Flood and Warren (2014) say that the PANLWT can be used for gross-flow analyses. The advantages of using LNKFW1MWT are not clear.

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**Author:** ![JeffBloem](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/jeffbloem/32/40_2.png) [@JeffBloem](https://forum.ipums.org/u/JeffBloem)\
**Post date:** [October 30, 2018, 3:57pm UTC](https://forum.ipums.org/t/which-longitudinal-weights-to-use/2641/2 "2018-10-30T15:57:00Z")

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The core difference between [PANLWT](https://cps.ipums.org/cps-action/variables/PANLWT#universe_section) and the [several longitudinal weights](https://cps.ipums.org/cps/cps_linking_documentation.shtml#linked_weights) is that the former is more general than each of the available latter weights. PANLWT is a longitudinal weight provided by the BLS that is (a) only available in basic monthly samples and (b) does not take into account many of the specific factors incorporated by the IPUMS-constructed longitudinal weights. The specific difference between PANLWT and [LNKFW1MWT](https://cps.ipums.org/cps-action/variables/LNKFW1MWT#universe_section) is in their universe statements. PANLWT is available for anyone over 15 years old who is able to be linked (forward or backward) month to month. LNKFW1MWT is available for all individuals who are eligible to link to the next month. So, for some individuals PANLWT is available and LNKFW1MWT is not available and for other individuals the reverse is true. The decision to use one of these weights over the other will depend on the specifics of your data set and research question.