Electronic Discovery - Time Zones

Electronic Discovery – Time Zone

In a previous article, I began a discussion about processing electronic discovery. One of the decisions we need to make before we begin processing electronic discovery is related to time zone. Most of the software used in our industry to perform processing will require a setting for the time zone. If all of the email custodians are located in the same time zone, it is easy to tell your service provider what time zone to use. However, this seemingly simple decision can get quite complicated.

My wonderful friend, Matthew Golab, a litigation support manager in Australia, has volunteered to write the rest of this article and share his knowledge. You may remember Matthew from my trip to ILTA or my podcast episode we recorded together. Matthew is one very smart guy.

Typically in eDiscovery you don't tend to think much about timezones for your data, in that either you standardise your processing for your office, or the vendor that you use has their own standardisation. When you do have to think about timezones in eDiscovery, it can be at times quite difficult.

I believe that most emails are all sent/received without a timezone offset, and then the local email client applies your timezone offset for you.

When dealing with multi-national companies, timezones can be quite important and you may find that you have to render using a local timezone offset for the custodian, however so that you are able to sort and filter chronologically in your legal review system, you may then choose to have a common timezone offset for all documents. When we do this, we then will maintain several metadata fields for each document so that we're able to easily convert and sort between timezones.

Let's assume that the bulk of our data is from Sydney during daylight savings which is AEDT or UTC+11, and that one custodian is based in Perth which is AWST or UTC+8. Therefore we may choose to have four metadata fields pertaining to dates in the database being:

UTC offset
Maindate UTC+11 All data is processed at this offset, including the data from the Perth custodian.
Date_PER UTC+8 All data is conformed to this offset, so for Sydney custodians their maindate value of say 15:30, would be 12:30 in this field
Date_UTC UTC+0 All data without a date offset – deduplication is typically run without a date offset applied
Custodian_Timezone N/A The UTC offset for the custodian

As you can see from the above, we now have three fields for all documents so that if needed we are able to chronologically sort all documents. This is particularly useful if for example we are interviewing the Perth custodian as we are able to show them Sydney documents at their local time.

In addition to the above, the Perth custodians documents would be rendered at their local time (UTC+8), whereas the Sydney custodians' documents would be rendered at UTC+11. A further complication to this approach is deduplication across custodians ie where you have culled duplicates from the Perth custodian, where the unique document is from a Sydney custodian as the documents will be rendered at UTC+11.

In Australia we span three timezones being:

Time offset Code Name City/States
UCT+10 AEST Australian Eastern Standard Time Sydney, NSW; Melbourne, VIC; Canberra, ACT
UCT+9.5 ACST Australian Central Standard Time Adelaide, SA; Darwin, NT
UCT+8.45 ACWST Australian Central Western Standard Time Before researching this I'd never heard of this timezone
UCT+8 AWST Australian Western Standard Time Perth, WA

To further complicate matters, some but not all of these timezones apply a daylight saving offset of +1hr.

The United States has similar complications given there are largely four timezones in use (that is excluding Alaska, Hawaii and other).

Offset Code Name Example City
UTC -8 PST Pacific Standard Time Los Angeles
UTC -7 MST Mountain Standard Time Salt Lake City
UTC -6 CST Central Standard Time Chicago
UTC -5 EST Eastern Standard Time New York

In comparison, when we work with European clients, it’s a relative breeze in that as a general rule of thumb the UK is UTC+0 (or +1 when in daylight savings), and Western Europe (Spain, France, Germany, Italy through to Poland) are UTC+1 or +1 in daylight savings.

You may also have noticed that I've been using UTC (Coordinated Universal Time) instead of the old fashioned GMT (Greenwich Mean Time). To all intents and purposes they are the same thing, however UTC is more precise as it is based upon atomic clocks.

Here is the definition from the Oxford English Dictionary:

An internationally accepted standard time corresponding to mean solar time at the Greenwich meridian, calculated from midnight as zero; spec. (more fully Coordinated Universal Time; also Universal Time Coordinated, Universal Coordinated Time) an international timekeeping standard calculated using International Atomic Time and adjusted to accommodate the difference between atomic time and solar time by the periodic addition of a leap second to account for irregularities in the Earth's rotation. Abbreviated UT, UTC.Although Universal Time has officially superseded the use of Greenwich Mean Time, the latter term is still used informally to refer to Universal Time. UT has generally been equivalent to GMT, except that, prior to the year 1925, GMT was reckoned from noon for astronomical purposes. The addition of leap seconds began on 1st January 1972. Times in astronomy are usually expressed in UT.

[1848   Blackwood's Mag. Mar. 357/2   Perhaps our excellent councillors are not aware that there is no such thing as a universal time. There is no peculiar virtue in the Greenwich time.]

1882   Monthly Notices Royal Astron. Soc. 42 205   The American Meteorological Society further considered it desirable that in the future a universal time reckoned from the meridian 180° from that of Greenwich should be generally introduced.

1929   Trans. Internat. Astron. Union 3 224   The terms Greenwich Civil Time (G.C.T.), Weltzeit (W.Z.) and Universal Time (U.T.) denote time measured from Greenwich Mean Midnight, and are not ambiguous.

1960   Federal Reg. 31 Dec. 14052/1   On January 1, 1961, the National Bureau of Standards will commence a regular broadcast..of a timing code which gives the day, hour, minute and second (Universal Time) and which is locked in phase to the frequency and time signals.

1970   Science 16 Jan. 278/3   To obtain the mass of Mars, we fitted Doppler data from 26 July, 5 days before encounter, to 31 July, 04:39:57 (Universal Time Coordinated).

1981   Science 30 Jan. 441/1   At approximately 3 a.m. (7:59:04.3 coordinated universal time) on 12 December 1979, Colombia and Ecuador were shaken by a major earthquake.

1999   Sky & Telescope Oct. 116/3   Universal Time (UT or UTC) is used worldwide by astronomers and others to avoid confusion between time zones.

2008   Times (Nexis) 20 June 37   Today 11.59pm Universal Co-ordinated Time (UTC) is the summer solstice.


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