I think that the Filling Up the Gaps report released in 2003 http://www.international.icomos.org/world_heritage/gaps.pdf
was an important initiative by Unesco to change the trend and make the WH list a more balanced one. As has already been often commented on in this forum by me and others this has had only limited impact, although it does appear things slowly begin to change. I would like to dedicate this thread to discussions regarding past and future successes and failiures in implementing this report across the different categories it refers to:
typological (A), chronological-regional (B) and thematic (C).
Other gaps that are also mentioned in the report but are not thoroughly discussed are the regional gap (let's call it D) and the bias in favour of cultural sites compared to natural and mixed ones (let's call it E).
I suggest we should look into each of these gaps separately and answer the following questions:
1) Has this gap decreased in the decade that passed since its publication? To which extent?
2) What are the main obstacles that still have to be addressed? Can we see any progress in this direction?

I would like to start with D which is relatively easy to calculate. I have already written in this forum about the overrepresentation of Europe in the list.
Europe's share should be 7% according to its territory (when considering only landmass - if we considered marine sites this figure would become even much smaller), 11% according to its human population, 14% according to the division of continents (with two Americas and Asia counting as two due to its scale) and 22% according to its number of recognized independent countries.
Filling up the gaps would probably have to mean lower feagures than these since Europe has always been highly overrepresented on the list. The real rate of European inscriptions, however, has remained excessive. Here are the rates since 2004, when the "Filling up the Gaps" report was released:

2004 41%
2005 37%
2006 28%
2007 32%
2008 33%
2009 46% (!)
2010 9% (the only year within boundaries!)
2011 28%
2012 23% (close to the upper boundary)

If we have a look at the known candidates for the next four years we will come at the following figures:

2013 32%
2014 43%
2015 30%
2016 22% (close to the upper boundary, but things might still change a lot)

A related problem is that a small number of counrties is responsible of most of the new nominations. I will hereby ignore the largest 7 countries in the world (Russia, Canada, China, USA, Australia, Brazil and India) which might justify their overproportionate representation by their relative size.
Omitting them we remain with the following countries that are greatly overrepresented:
Italy, Spain, France, UK, Germany, Mexico, Greece, Japan, Iran, Sweden, Portugal, Poland and Czech Rep (all together 13 countries, compared to more than 170 countries remaining!).
In doing the calculation I counted transnational sites as belonging to the less represented countries. I also counted non proper territories (Reunion, New Caledonia, Hawaii) as distinct countries. These factors should help reducing the overrepresentation of the above mentioned countries in the calculation. Nonetheless, I still came up with very high figures.
Omitting the nominations of the 7 largest countries these 13 countries are responsible of the following percentage from the total of new nominations:

2004 38%
2005 27%
2006 44%
2007 35%
2008 25%
2009 42%
2010 40%
2011 30%
2012 35%

Answering the questions above I think we could sum up that in category D (regional bias) Europe is not only greatly overrepresented. There is also no clear trend showing a reduction of its new nominations. The same is also true of a small number of overrepresented countries most of which are also European.
What can be done? Any suggestions?

I am not entirely sure of the validity/usefulness of a statistical analysis based on region/landmass/population etc - the Type D "gap" above. Does it really demonstrate a "Gap"? It certainly shows an "imbalance" but is not necessarily relevant to understanding the "gaps" as defined in the A/B/C typological, chronological-regional and thematic categories. If we accept the categorisation of gaps under these 3 categories (bearing in mind that the analysis was carried out by ICOMOS and therefore only covered Cultural sites - but there are similar papers from IUCN on "Natural" gaps) then, presumably, filling those "gaps" would result in a "state of grace" being achieved - whatever regional "imbalance" it also resulted in (many "gaps" are also in effect regional ones so their filling must alter the regional balance to some extent)? So, what sort of statistical "balance" would emerge from such a state? It may not be PC to say so, but not all countries are equally "endowed" regarding tangible cultural and natural heritage – as these are defined. But then not all countries are equally endowed regarding intangible heritage or anything else for that matter. Filling "gaps" based on A/B/C criteria wouldn't necessarily result in any sort of statistical balance. As long as the list is intended to be based on such criteria (rather than a "prize" handed out to every country on some basis of "fairness"/"equality") then such imbalances are going to occur. OK – that for Europe at the moment is so large that it probably isn't justifiable as an "end state". But why might this be?

Firstly, there are surely 2 separate issues regarding the imbalance of the current list and likely future inscriptions
a. Gaps
b. Duplication

Clearly "worthwhile"/significant "gaps" should be filled but I have never been totally sure what the attitude is/should be towards "duplication". One approach is that the List only needs "one" of every type of site (a "representative" model) - another is that it should have as many of every type of site as have "OUV" (a "unique" model). But, presumably the more of something there is then the less its "outstandingness" becomes? To take things to extreme - if there were 10 Taj Mahals in this World should they all be inscribed or would the mere fact that there were 10 of them reduce the OUV of each of them - or at least of the 9 which had not got in first? This is in effect the situation we are in regarding e.g Gothic cathedrals and would seem to be a significant reason (among many others) for there being so many European sites - albeit that the "duplication" is dressed up with enough "uniqueness" to obfuscate the fact!. And in any case, are all those African cultural landscapes any different with regard to their own individual "uniqueness"?

The issue of "Replication" only becomes important if there is a wish to ration the total number of inscribed sites. Such "rationing" could arise from
a. The practical issues of assessing/monitoring large numbers of sites if every inscription has a cost in terms of preventing some other more/equally worthwhile site which may actually fill a gap, from being evaluated and, possibly, inscribed.
b. A decision that duplication is per se "bad" and that the List should avoid it - either totally (unrealistic since there is already so much of it!) or at least in future.

I see no evidence that the first is actually happening - there are already policies in place to ensure that unrepresented countries and site-types get priority each year. It may be true that those countries which are nominating "duplicates" could have spent the money they used to produce the nomination by helping some other country to fill a gap. But the slowness from many countries with "gap sites" in coming forward with viable nominations is only partly a matter of simple lack of money to prepare a nomination but rather more fundamental matters such as lack of "capability" which take years to overcome.

The European statistical imbalance (I won't call it a "gap") could arise from some (or all) of the following reasons
a. It genuinely has more sites meeting the OUV criteria as currently defined than other regions – if there is a problem it lies in the definition of OUV which is Eurocentric even after all the attempts to widen it. But, possibly, the reality of the "Tangible Heritage" domain just is that it favours Europe, and that other countries should look for other areas of human endeavour to exercise their legitimate desire for recognition and "superiority" (e.g religious fervour, contemporary music, sport , creating future tangible heritage by building skyscrapers/new cities etc etc!!)
b. It has done a better job than other regions in getting its OUV sites inscribed – ie the problem is not its OVER representation but the UNDER representation of elsewhere. Europe may have to take some blame for this (colonial guilt etc) and could possibly do more to change cultures in other countries to enable them to gain more inscriptions but there is no short term fix for this.
c. It is getting sites inscribed which are "duplicates" of other sites and may or may not have OUV depending on the attitude to be taken towards recognising OUV in duplicate/representational sites.
d. It is getting sites inscribed which do NOT have OUV but is somehow "conning" the system – political influence, good presentation etc etc. If so, I might suggest that there are examples also of non European sites with qustionable OUV getting inscribed through "political influence"!
e. Because of its own hyper-activity it is preventing non European sites with OUV from gaining inscription. As per the above, I would suggest that this is not the case

Actually, I think that a run through the "gaps" as shown in the ICOMOS A/B/C analysis will show that there has been progress in filling them since it was written (a subject for a further "post" I feel!). In any case I don't think that the continuing high numbers of European inscriptions can be blamed for any failure to fill them. I would also point out that the ICOMOS analysis contains some "suspect" aspects –for instance it seems to suggest that there would be merit in further Viticulture sites being inscribed!

The current issue of the World Heritage magazine is about SIDS (Small Island Developing States). This is one group of countries that has been underrepresented, but in recent years has appeared on the scene (Palau, Vanuatu, Barbados, Marshall Islands etc). The question is if these tiny countries really have something that is outstanding on world level. The WH magazine reports about an "upstream process" that has been started for the Grenadine Island Group (transboundary Grenada, St. Vincent and the Grenadines), but that they're still searching for a valuable nomination.

South Africa seems to be on the viticulture track too: http://www.fm.co.za/business/2013/02/18/boschendal-considered-for-world-heritage-stat us

Even if all the pending or soon to be evaluated nominations for small island nations were inscribed in the next couple years, it will not make the list suddenly balanced. If this occurred there would likely be a lack of sites put forward over time, because really how many OUV sites can possibly be found on a small island?

Solvigants reasons for an imbalance, particularly a,b,c taken together seem to be what is currently happening. Europe has a rich history, they develop and submit excellent nomination files, and Europe has been highly successful with "duplicate" sites.

The East Asian bloc of China, Korea, Japan, and Vietnam has been just as successful as many European countries. I would attribute this to the same reasons as Europe a,b,c. Though I would argue not to the same degree as Europe concerning "duplicate" sites.

To actually solve a perceived imbalance problem, one must locate sites in underepresented countries that demonstrate OUV. What countries are these sites located in? The considered countries should have the potential to follow the a,b,c route of inscriptions.

Philippines, Turkey, Egypt, Kenya, Ethiopia, Iraq, Indonesia, India, Guatemala, Peru, Myanmar, Bhutan, Taiwan, Malaysia, Cambodia, Laos

All 16 of these state entities has a rich culture and has the potential to nominate a large number of sites that could demonstrate OUV. Some have become more and more successful lately, exp Turkey and Ethiopia. India is a country that should have far more inscriptions than what we see currently, I think it is well known why some of India's nominations fail or are endlessly delayed. What relates all of these places concerning world heritage is their previously sub-standard progress with reasons b, c. Once these countries with the potential to earn several inscriptions make inroads into the b and c paths, the world heritage list will become more balanced.

On a side note: Though a western country, I would also consider the United States under-represented, but that is perhaps left for a different discussion. I also don't think the US and Canada should be included together with Europe when Unesco categorizes regions.

Taking up on Solivagant's suggestion here are gaps listed by ICOMOS under A, B and C:

A:
1) pastoralist cultures
2) traditional production of crops such as wheat, barley,
maize, millet, cocoa, cotton, rubber, or fruits
3) historic and traditional irrigation systems
4) human seasonal migration (transhumance)
5) sacred and/or symbolic significance of certain natural
features such as mountains, volcanoes, forests, groves, etc
6) African, Asian and Pacific vernacular architecture
7) Non European technological properties
8) pre-industrial revolution technological properties (mining sites excluded)
9) sites representing Islam, Buddhism, Hinduism, and Judaism
10) modern heritage
11) cultural landskapes in Arab countries
12) African archaeology, rock art, cultural routes and burial sites

Ok, looking at the gaps in Cat A as defined above by Assif.
I have taken all Cultural and Mixed inscriptions from 2005-12 inclusive (8 yrs). This, on the basis that the report on "Filling the Gaps" dated 2003 couldn't have had any impact before the 2005 WHC.
In this period there were 139 Cultural and Mixed (of which mixed was only 4) inscriptions. Out of interest there were an additional 37 Natural ones

The 139 were split across geographical (but not UNESCO "political") regions as follows (obviously there can be "arguments" about this allocation!)
43 Eur
15 Latin Am + Carib
17 Middle East + N Africa. (Inc Turkey and Israel but not Iran. N African littoral states to Morocco)
19 Rem of Africa
36 Rem of Asia.
6 Oceania (Inc Oz/PNG)
2 N America (US inc Hawaiii and Canada)
10 of the above were situated in a SIDS state.
None of the Cultural/mixed inscriptions were for a territory of a State which was located outside its geographic area other than Hawaii. Similarly there was no issue with multi -state sites

Of the 139 inscriptions, I reckon that 40 can reasonably be assigned to at least 1 of the 12 categories -quite a high percentage!! But it could be of course that the authors of the report were aware of what was coming along.

Herewith the allocation of the 40 by Category (again there might be some argument at the edges!)
1) Pastoralist cultures - 2 (Grand Pre, Richtersved)
2) Traditional production of crops such as wheat, barley, maize, millet, cocoa, cotton, rubber, or fruits - 1 (Columbian coffee)
3) Historic and traditional irrigation systems - 3 (Shushtar, Aflaj, Bali Subak)
4) human seasonal migration (transhumance) - 1 (Causses)
5) Sacred and/or symbolic significance of certain natural features such as mountains, volcanoes, forests, groves, etc - 5 (Osun-Osogbo, Le Morne, Mijikenda forests, Mt Wutai, Suleman-too,
6) African, Asian and Pacific vernacular architecture- 1 (Hahoe/Yangdong, Kaipeng, Tulou, some of the CLs could have been assigned here too)
7) Non European technological properties - 5 (Sta Laura saltpeter, Tequila, Yin Xu, Jantar Mantars, Sewell)
8) Pre-industrial revolution technological properties (mining sites excluded) - 1 (Plantin Moretus)
9) Sites representing Islam, Buddhism, Hinduism, and Judaism - 6 (Preah Vihear, Deng Feng, Ardabil, Hiraizumi, Bali Subak, Masjid e-Jami. The non christina Bahai perhpas could have been included)
10) Modern heritage - 7 (Le Havre, UNAM, Sydney opera, Berlin modernism, Stoclet, Bikini, Fagus, Centennial Hall)
11) Cultural landscapes in Arab countries - 2 (Al Ain, Wadi Rum)
12) African archaeology, rock art, cultural routes and burial sites - 8 (Chongoni, Kondoa, Senegambian circles, Twyfelfontein, Loropeni (could have been under Non Eur Technol) , Meroe, Saloum, Lope-Okanda

And now to category B:

1) Ancient Mesopotamian cultures
2) Anatolian cultures
3) Ancient Egypt
4) Seljuk and Ottoman Empires
5) Central Asia (cultural)
6) Pacific except Australia (cultural)
7) Central Africa (cultural), e.g. Bantu states
8) Post independence sites from the Americas
9) Precolumbian cultures (except Mayan)

and category C:

1) expressions of oral traditions,
music, education, philosophy, health and justice
2) rural settlements
3) modern towns (19th century onward)
4) necropolises
5) industrial landscapes
6) Zoroastrianism
7) living indigenous beliefs
8) hunting-gathering-fishing
9) places of mythical origin (whatever this should mean!)
10) cultural routes
11) migration-nomadism-slavery
12) land roads
13) aviation
14) energy conversion and utilisation (wind power,
water energy, steam, coal, electricity, thermonuclear energy,
etc.)

Solivagant, you are right. Maybe the implementation isn't that bad after all (You forgot Sewell (2006) by the way).
It would be great if you could attmept to apply the same analysis to the next two categories too. We might have some interesting conclusions then.

Herewith Cat B (With this and the Cat C to follow there may well be a degree of "post hoc fitting" - whether some of them were actually nominated and inscribed with the Fillinng the gaps category one can't be sure!

1) Ancient Mesopotamian cultures - 0 (Oman/Dilmun might be regarded as a fit?)
2) Anatolian cultures - 1 (Catalhoyuk)
3) Ancient Egypt - 1 (Meroe)
4) Seljuk and Ottoman Empires - 4 (Selimiye, Berat, Mostar, Visegrad Bridge)
5) Central Asia (cultural) - 7 (Konye-Urgenche, Soltaniye, Gobustan, Nisa, Suleman-too, Sarazm, Gonbad)
6) Pacific except Australia (cultural) - 5 (Papahanaumokuakea, Rock islands, Bikini, Kuk, Roi Mata)
7) Central Africa (cultural), e.g. Bantu states - 1 (Lope-Okanda)
8) Post independence sites from the Americas - 3 (Santa Laura, Cienfuegos, Sewell)
9) Precolumbian cultures (except Mayan) - 2 (Yagul, Caral-supe)

And Cat C

1) Expressions of oral traditions, music, education, philosophy, health and justice - 0
2) Rural settlements - 11 (Halsingland, Bassari, Konso, Tramuntana, Villages of N Syria, Stari Grad, Coffee Landscape, Hahoe, Kaipeng, Tulou)
3) Modern towns (19th century onward) - 5 (le Havre, Sewell, Berlin modernism, Grand bassam, Rabat)
4) Necropolises - 1 - (Royal Joseon)
5) Industrial landscapes - 7 (Nord Pas, Wallonia, Heritage of Mercury, Chaux de Fonds, Iwami ginzan, Cornwall/W Devon, Tequila)
6) Zoroastrianism - 0
7) Living indigenous beliefs - 4 (Roi Mata, Kondoa, Chongoni, Osun-Osogbo,
8) Hunting-gathering-fishing - 5 (Richtersveld, Twyfelfontein, Saloum, Papahanaumokuakea, Rock islands)
9) Places of mythical origin (whatever this should mean!) - 1 (Dengfeng)
10) Cultural routes - 1 (Negev)
11) Migration-nomadism-slavery - 3 (Bridgetown. Le morne, Aapravasi)
12) Land roads - 1 (Camino Real)
13) Aviation - 0
14) Energy conversion and utilisation (wind power, water energy, steam, coal, electricity, thermonuclear energy etc.) - 1 (Bikini)

Phew....!

1) Expressions of oral traditions, music, education, philosphy, health and justice

2) Rural Settlements

I would include the Historic Villages of Korea: Hahoe and Yangdong